forked from OSchip/llvm-project
AMDGPU: Fix annotating loops with nested loop conditions
If the branch condition for a loop was a phi which itself was fed from a phi from a loop, it isn't safe to try to delete the phi until after the loop is handled. llvm-svn: 298737
This commit is contained in:
Matt Arsenault
parent
6a1209ee87
commit
0607a4427b
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@ -22,6 +22,7 @@
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#include "llvm/IR/Module.h"
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#include "llvm/Pass.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Transforms/Utils/Local.h"
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#include "llvm/Transforms/Utils/SSAUpdater.h"
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using namespace llvm;
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@ -77,7 +78,8 @@ class SIAnnotateControlFlow : public FunctionPass {
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void insertElse(BranchInst *Term);
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Value *handleLoopCondition(Value *Cond, PHINode *Broken,
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llvm::Loop *L, BranchInst *Term);
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llvm::Loop *L, BranchInst *Term,
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SmallVectorImpl<WeakVH> &LoopPhiConditions);
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void handleLoop(BranchInst *Term);
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@ -183,8 +185,9 @@ bool SIAnnotateControlFlow::isElse(PHINode *Phi) {
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// \brief Erase "Phi" if it is not used any more
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void SIAnnotateControlFlow::eraseIfUnused(PHINode *Phi) {
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if (!Phi->hasNUsesOrMore(1))
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Phi->eraseFromParent();
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if (llvm::RecursivelyDeleteDeadPHINode(Phi)) {
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DEBUG(dbgs() << "Erased unused condition phi\n");
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}
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}
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/// \brief Open a new "If" block
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@ -208,8 +211,10 @@ void SIAnnotateControlFlow::insertElse(BranchInst *Term) {
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}
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/// \brief Recursively handle the condition leading to a loop
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Value *SIAnnotateControlFlow::handleLoopCondition(Value *Cond, PHINode *Broken,
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llvm::Loop *L, BranchInst *Term) {
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Value *SIAnnotateControlFlow::handleLoopCondition(
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Value *Cond, PHINode *Broken,
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llvm::Loop *L, BranchInst *Term,
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SmallVectorImpl<WeakVH> &LoopPhiConditions) {
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// Only search through PHI nodes which are inside the loop. If we try this
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// with PHI nodes that are outside of the loop, we end up inserting new PHI
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@ -233,14 +238,14 @@ Value *SIAnnotateControlFlow::handleLoopCondition(Value *Cond, PHINode *Broken,
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}
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Phi->setIncomingValue(i, BoolFalse);
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Value *PhiArg = handleLoopCondition(Incoming, Broken, L, Term);
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Value *PhiArg = handleLoopCondition(Incoming, Broken, L,
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Term, LoopPhiConditions);
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NewPhi->addIncoming(PhiArg, From);
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}
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BasicBlock *IDom = DT->getNode(Parent)->getIDom()->getBlock();
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for (unsigned i = 0, e = Phi->getNumIncomingValues(); i != e; ++i) {
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Value *Incoming = Phi->getIncomingValue(i);
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if (Incoming != BoolTrue)
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continue;
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@ -276,7 +281,7 @@ Value *SIAnnotateControlFlow::handleLoopCondition(Value *Cond, PHINode *Broken,
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NewPhi->setIncomingValue(i, PhiArg);
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}
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eraseIfUnused(Phi);
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LoopPhiConditions.push_back(WeakVH(Phi));
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return Ret;
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}
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@ -318,14 +323,21 @@ void SIAnnotateControlFlow::handleLoop(BranchInst *Term) {
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BasicBlock *Target = Term->getSuccessor(1);
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PHINode *Broken = PHINode::Create(Int64, 0, "phi.broken", &Target->front());
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SmallVector<WeakVH, 8> LoopPhiConditions;
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Value *Cond = Term->getCondition();
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Term->setCondition(BoolTrue);
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Value *Arg = handleLoopCondition(Cond, Broken, L, Term);
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Value *Arg = handleLoopCondition(Cond, Broken, L, Term, LoopPhiConditions);
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for (BasicBlock *Pred : predecessors(Target))
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Broken->addIncoming(Pred == BB ? Arg : Int64Zero, Pred);
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Term->setCondition(CallInst::Create(Loop, Arg, "", Term));
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for (WeakVH Val : reverse(LoopPhiConditions)) {
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if (PHINode *Cond = cast_or_null<PHINode>(Val))
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eraseIfUnused(Cond);
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}
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push(Term->getSuccessor(0), Arg);
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}
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@ -0,0 +1,269 @@
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; RUN: opt -mtriple=amdgcn-- -S -structurizecfg -si-annotate-control-flow %s | FileCheck -check-prefix=IR %s
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; RUN: llc -march=amdgcn -mcpu=hawaii -verify-machineinstrs < %s | FileCheck -check-prefix=GCN %s
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; After structurizing, there are 3 levels of loops. The i1 phi
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; conditions mutually depend on each other, so it isn't safe to delete
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; the condition that appears to have no uses until the loop is
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; completely processed.
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; IR-LABEL: @reduced_nested_loop_conditions(
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; IR: bb5:
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; IR-NEXT: %phi.broken = phi i64 [ %loop.phi, %bb10 ], [ 0, %bb ]
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; IR-NEXT: %tmp6 = phi i32 [ 0, %bb ], [ %tmp11, %bb10 ]
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; IR-NEXT: %tmp7 = icmp eq i32 %tmp6, 1
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; IR-NEXT: %0 = call { i1, i64 } @llvm.amdgcn.if(i1 %tmp7)
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; IR-NEXT: %1 = extractvalue { i1, i64 } %0, 0
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; IR-NEXT: %2 = extractvalue { i1, i64 } %0, 1
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; IR-NEXT: br i1 %1, label %bb8, label %Flow
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; IR: bb8:
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; IR-NEXT: %3 = call i64 @llvm.amdgcn.break(i64 %phi.broken)
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; IR-NEXT: br label %bb13
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; IR: bb10:
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; IR-NEXT: %loop.phi = phi i64 [ %6, %Flow ]
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; IR-NEXT: %tmp11 = phi i32 [ %5, %Flow ]
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; IR-NEXT: %4 = call i1 @llvm.amdgcn.loop(i64 %loop.phi)
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; IR-NEXT: br i1 %4, label %bb23, label %bb5
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; IR: Flow:
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; IR-NEXT: %loop.phi1 = phi i64 [ %loop.phi2, %bb4 ], [ %phi.broken, %bb5 ]
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; IR-NEXT: %5 = phi i32 [ %tmp21, %bb4 ], [ undef, %bb5 ]
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; IR-NEXT: %6 = call i64 @llvm.amdgcn.else.break(i64 %2, i64 %loop.phi1)
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; IR-NEXT: call void @llvm.amdgcn.end.cf(i64 %2)
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; IR-NEXT: br label %bb10
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; IR: bb13:
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; IR-NEXT: %loop.phi3 = phi i64 [ %loop.phi4, %bb3 ], [ %3, %bb8 ]
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; IR-NEXT: %tmp14 = phi i1 [ false, %bb3 ], [ true, %bb8 ]
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; IR-NEXT: %tmp15 = bitcast i64 %tmp2 to <2 x i32>
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; IR-NEXT: br i1 %tmp14, label %bb16, label %bb20
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; IR: bb16:
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; IR-NEXT: %tmp17 = extractelement <2 x i32> %tmp15, i64 1
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; IR-NEXT: %tmp18 = getelementptr inbounds i32, i32 addrspace(3)* undef, i32 %tmp17
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; IR-NEXT: %tmp19 = load volatile i32, i32 addrspace(3)* %tmp18
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; IR-NEXT: br label %bb20
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; IR: bb20:
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; IR-NEXT: %loop.phi4 = phi i64 [ %phi.broken, %bb16 ], [ %phi.broken, %bb13 ]
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; IR-NEXT: %loop.phi2 = phi i64 [ %phi.broken, %bb16 ], [ %loop.phi3, %bb13 ]
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; IR-NEXT: %tmp21 = phi i32 [ %tmp19, %bb16 ], [ 0, %bb13 ]
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; IR-NEXT: br label %bb9
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; IR: bb23:
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; IR-NEXT: call void @llvm.amdgcn.end.cf(i64 %loop.phi)
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; IR-NEXT: ret void
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; GCN-LABEL: {{^}}reduced_nested_loop_conditions:
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; GCN: s_cmp_eq_u32 s{{[0-9]+}}, 1
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; GCN-NEXT: s_cbranch_scc1
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; FIXME: Should fold to unconditional branch?
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; GCN: s_mov_b64 vcc, -1
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; GCN-NEXT: ; implicit-def
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; GCN: s_cbranch_vccz
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; GCN: ds_read_b32
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; GCN: [[BB9:BB[0-9]+_[0-9]+]]: ; %bb9
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; GCN-NEXT: ; =>This Inner Loop Header: Depth=1
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; GCN-NEXT: s_branch [[BB9]]
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define amdgpu_kernel void @reduced_nested_loop_conditions(i64 addrspace(3)* nocapture %arg) #0 {
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bb:
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%tmp = tail call i32 @llvm.amdgcn.workitem.id.x() #1
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%tmp1 = getelementptr inbounds i64, i64 addrspace(3)* %arg, i32 %tmp
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%tmp2 = load volatile i64, i64 addrspace(3)* %tmp1
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br label %bb5
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bb3: ; preds = %bb9
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br i1 true, label %bb4, label %bb13
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bb4: ; preds = %bb3
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br label %bb10
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bb5: ; preds = %bb10, %bb
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%tmp6 = phi i32 [ 0, %bb ], [ %tmp11, %bb10 ]
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%tmp7 = icmp eq i32 %tmp6, 1
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br i1 %tmp7, label %bb8, label %bb10
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bb8: ; preds = %bb5
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br label %bb13
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bb9: ; preds = %bb20, %bb9
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br i1 false, label %bb3, label %bb9
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bb10: ; preds = %bb5, %bb4
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%tmp11 = phi i32 [ %tmp21, %bb4 ], [ undef, %bb5 ]
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%tmp12 = phi i1 [ %tmp22, %bb4 ], [ true, %bb5 ]
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br i1 %tmp12, label %bb23, label %bb5
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bb13: ; preds = %bb8, %bb3
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%tmp14 = phi i1 [ %tmp22, %bb3 ], [ true, %bb8 ]
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%tmp15 = bitcast i64 %tmp2 to <2 x i32>
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br i1 %tmp14, label %bb16, label %bb20
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bb16: ; preds = %bb13
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%tmp17 = extractelement <2 x i32> %tmp15, i64 1
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%tmp18 = getelementptr inbounds i32, i32 addrspace(3)* undef, i32 %tmp17
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%tmp19 = load volatile i32, i32 addrspace(3)* %tmp18
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br label %bb20
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bb20: ; preds = %bb16, %bb13
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%tmp21 = phi i32 [ %tmp19, %bb16 ], [ 0, %bb13 ]
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%tmp22 = phi i1 [ false, %bb16 ], [ %tmp14, %bb13 ]
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br label %bb9
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bb23: ; preds = %bb10
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ret void
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}
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; Earlier version of above, before a run of the structurizer.
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; IR-LABEL: @nested_loop_conditions(
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; IR: Flow7:
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; IR-NEXT: call void @llvm.amdgcn.end.cf(i64 %17)
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; IR-NEXT: %0 = call { i1, i64 } @llvm.amdgcn.if(i1 %15)
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; IR-NEXT: %1 = extractvalue { i1, i64 } %0, 0
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; IR-NEXT: %2 = extractvalue { i1, i64 } %0, 1
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; IR-NEXT: br i1 %1, label %bb4.bb13_crit_edge, label %Flow8
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; IR: Flow1:
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; IR-NEXT: %loop.phi = phi i64 [ %loop.phi9, %Flow6 ], [ %phi.broken, %bb14 ]
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; IR-NEXT: %13 = phi <4 x i32> [ %29, %Flow6 ], [ undef, %bb14 ]
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; IR-NEXT: %14 = phi i32 [ %30, %Flow6 ], [ undef, %bb14 ]
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; IR-NEXT: %15 = phi i1 [ %31, %Flow6 ], [ false, %bb14 ]
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; IR-NEXT: %16 = phi i1 [ false, %Flow6 ], [ %8, %bb14 ]
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; IR-NEXT: %17 = call i64 @llvm.amdgcn.else.break(i64 %11, i64 %loop.phi)
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; IR-NEXT: call void @llvm.amdgcn.end.cf(i64 %11)
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; IR-NEXT: %18 = call i1 @llvm.amdgcn.loop(i64 %17)
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; IR-NEXT: br i1 %18, label %Flow7, label %bb14
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; IR: Flow2:
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; IR-NEXT: %loop.phi10 = phi i64 [ %loop.phi11, %Flow5 ], [ %12, %bb16 ]
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; IR-NEXT: %19 = phi <4 x i32> [ %29, %Flow5 ], [ undef, %bb16 ]
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; IR-NEXT: %20 = phi i32 [ %30, %Flow5 ], [ undef, %bb16 ]
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; IR-NEXT: %21 = phi i1 [ %31, %Flow5 ], [ false, %bb16 ]
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; IR-NEXT: %22 = phi i1 [ false, %Flow5 ], [ false, %bb16 ]
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; IR-NEXT: %23 = phi i1 [ false, %Flow5 ], [ %8, %bb16 ]
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; IR-NEXT: %24 = call { i1, i64 } @llvm.amdgcn.if(i1 %23)
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; IR-NEXT: %25 = extractvalue { i1, i64 } %24, 0
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; IR-NEXT: %26 = extractvalue { i1, i64 } %24, 1
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; IR-NEXT: br i1 %25, label %bb21, label %Flow3
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; IR: bb21:
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; IR: %tmp12 = icmp slt i32 %tmp11, 9
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; IR-NEXT: %27 = xor i1 %tmp12, true
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; IR-NEXT: %28 = call i64 @llvm.amdgcn.if.break(i1 %27, i64 %phi.broken)
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; IR-NEXT: br label %Flow3
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; IR: Flow3:
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; IR-NEXT: %loop.phi11 = phi i64 [ %phi.broken, %bb21 ], [ %phi.broken, %Flow2 ]
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; IR-NEXT: %loop.phi9 = phi i64 [ %28, %bb21 ], [ %loop.phi10, %Flow2 ]
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; IR-NEXT: %29 = phi <4 x i32> [ %tmp9, %bb21 ], [ %19, %Flow2 ]
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; IR-NEXT: %30 = phi i32 [ %tmp10, %bb21 ], [ %20, %Flow2 ]
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; IR-NEXT: %31 = phi i1 [ %27, %bb21 ], [ %21, %Flow2 ]
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; IR-NEXT: call void @llvm.amdgcn.end.cf(i64 %26)
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; IR-NEXT: br i1 %22, label %bb31.loopexit, label %Flow4
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; IR: bb31:
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; IR-NEXT: call void @llvm.amdgcn.end.cf(i64 %7)
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; IR-NEXT: store volatile i32 0, i32 addrspace(1)* undef
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; IR-NEXT: ret void
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; GCN-LABEL: {{^}}nested_loop_conditions:
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; GCN: v_cmp_lt_i32_e32 vcc, 8, v
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; GCN: s_and_b64 vcc, exec, vcc
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; GCN: s_cbranch_vccnz [[BB31:BB[0-9]+_[0-9]+]]
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; GCN: [[BB14:BB[0-9]+_[0-9]+]]: ; %bb14
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; GCN: v_cmp_ne_u32_e32 vcc, 1, v
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; GCN-NEXT: s_and_b64 vcc, exec, vcc
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; GCN-NEXT: s_cbranch_vccnz [[BB31]]
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; GCN: [[BB18:BB[0-9]+_[0-9]+]]: ; %bb18
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; GCN: buffer_load_dword
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; GCN: v_cmp_lt_i32_e32 vcc, 8, v
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; GCN-NEXT: s_and_b64 vcc, exec, vcc
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; GCN-NEXT: s_cbranch_vccnz [[BB18]]
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; GCN: buffer_load_dword
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; GCN: buffer_load_dword
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; GCN: v_cmp_gt_i32_e32 vcc, 9
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; GCN-NEXT: s_and_b64 vcc, exec, vcc
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; GCN-NEXT: s_cbranch_vccnz [[BB14]]
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; GCN: [[BB31]]:
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; GCN: buffer_store_dword
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; GCN: s_endpgm
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define amdgpu_kernel void @nested_loop_conditions(i64 addrspace(1)* nocapture %arg) #0 {
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bb:
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%tmp = tail call i32 @llvm.amdgcn.workitem.id.x() #1
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%tmp1 = zext i32 %tmp to i64
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%tmp2 = getelementptr inbounds i64, i64 addrspace(1)* %arg, i64 %tmp1
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%tmp3 = load i64, i64 addrspace(1)* %tmp2, align 16
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%tmp932 = load <4 x i32>, <4 x i32> addrspace(1)* undef, align 16
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%tmp1033 = extractelement <4 x i32> %tmp932, i64 0
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%tmp1134 = load volatile i32, i32 addrspace(1)* undef
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%tmp1235 = icmp slt i32 %tmp1134, 9
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br i1 %tmp1235, label %bb14.lr.ph, label %bb13
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bb14.lr.ph: ; preds = %bb
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br label %bb14
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bb4.bb13_crit_edge: ; preds = %bb21
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br label %bb13
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bb13: ; preds = %bb4.bb13_crit_edge, %bb
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br label %bb31
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bb14: ; preds = %bb21, %bb14.lr.ph
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%tmp1037 = phi i32 [ %tmp1033, %bb14.lr.ph ], [ %tmp10, %bb21 ]
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%tmp936 = phi <4 x i32> [ %tmp932, %bb14.lr.ph ], [ %tmp9, %bb21 ]
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%tmp15 = icmp eq i32 %tmp1037, 1
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br i1 %tmp15, label %bb16, label %bb31.loopexit
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bb16: ; preds = %bb14
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%tmp17 = bitcast i64 %tmp3 to <2 x i32>
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br label %bb18
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bb18: ; preds = %bb18, %bb16
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%tmp19 = load volatile i32, i32 addrspace(1)* undef
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%tmp20 = icmp slt i32 %tmp19, 9
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br i1 %tmp20, label %bb21, label %bb18
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bb21: ; preds = %bb18
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%tmp22 = extractelement <2 x i32> %tmp17, i64 1
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%tmp23 = lshr i32 %tmp22, 16
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%tmp24 = select i1 undef, i32 undef, i32 %tmp23
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%tmp25 = uitofp i32 %tmp24 to float
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%tmp26 = fmul float %tmp25, 0x3EF0001000000000
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%tmp27 = fsub float %tmp26, undef
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%tmp28 = fcmp olt float %tmp27, 5.000000e-01
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%tmp29 = select i1 %tmp28, i64 1, i64 2
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%tmp30 = extractelement <4 x i32> %tmp936, i64 %tmp29
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%tmp7 = zext i32 %tmp30 to i64
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%tmp8 = getelementptr inbounds <4 x i32>, <4 x i32> addrspace(1)* undef, i64 %tmp7
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%tmp9 = load <4 x i32>, <4 x i32> addrspace(1)* %tmp8, align 16
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%tmp10 = extractelement <4 x i32> %tmp9, i64 0
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%tmp11 = load volatile i32, i32 addrspace(1)* undef
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%tmp12 = icmp slt i32 %tmp11, 9
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br i1 %tmp12, label %bb14, label %bb4.bb13_crit_edge
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bb31.loopexit: ; preds = %bb14
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br label %bb31
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bb31: ; preds = %bb31.loopexit, %bb13
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store volatile i32 0, i32 addrspace(1)* undef
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ret void
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}
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declare i32 @llvm.amdgcn.workitem.id.x() #1
|
||||
|
||||
attributes #0 = { nounwind }
|
||||
attributes #1 = { nounwind readnone }
|
||||
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Reference in New Issue