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Broaden the definition of a "widenable branch" 

As a reminder, a "widenable branch" is the pattern "br i1 (and i1 X, WC()), label %taken, label %untaken" where "WC" is the widenable condition intrinsics. The semantics of such a branch (derived from the semantics of WC) is that a new condition can be added into the condition arbitrarily without violating legality.

Broaden the definition in two ways:
    Allow swapped operands to the br (and X, WC()) form
    Allow widenable branch w/trivial condition (i.e. true) which takes form of br i1 WC()

The former is just general robustness (e.g. for X = non-instruction this is what instcombine produces). The later is specifically important as partial unswitching of a widenable range check produces exactly this form above the loop.

Differential Revision: https://reviews.llvm.org/D70502
This commit is contained in:
Philip Reames 2019-11-21 10:44:13 -08:00
parent d9426c3360
commit aaea24802b
7 changed files with 455 additions and 26 deletions
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34
llvm/lib/Analysis/GuardUtils.cpp
View File

@ -13,9 +13,9 @@
#include "llvm/IR/PatternMatch.h"
using namespace llvm;
using namespace llvm::PatternMatch;
bool llvm::isGuard(const User *U) {
using namespace llvm::PatternMatch;
return match(U, m_Intrinsic<Intrinsic::experimental_guard>());
}
@ -32,7 +32,6 @@ bool llvm::isGuardAsWidenableBranch(const User *U) {
if (!parseWidenableBranch(U, Condition, WidenableCondition, GuardedBB,
DeoptBB))
return false;
using namespace llvm::PatternMatch;
for (auto &Insn : *DeoptBB) {
if (match(&Insn, m_Intrinsic<Intrinsic::experimental_deoptimize>()))
return true;
@ -45,17 +44,32 @@ bool llvm::isGuardAsWidenableBranch(const User *U) {
bool llvm::parseWidenableBranch(const User *U, Value *&Condition,
Value *&WidenableCondition,
BasicBlock *&IfTrueBB, BasicBlock *&IfFalseBB) {
using namespace llvm::PatternMatch;
if (match(U, m_Br(m_Intrinsic<Intrinsic::experimental_widenable_condition>(),
IfTrueBB, IfFalseBB)) &&
cast<BranchInst>(U)->getCondition()->hasOneUse()) {
WidenableCondition = cast<BranchInst>(U)->getCondition();
Condition = ConstantInt::getTrue(IfTrueBB->getContext());
return true;
}
// Check for two cases:
// 1) br (i1 (and A, WC())), label %IfTrue, label %IfFalse
// 2) br (i1 (and WC(), B)), label %IfTrue, label %IfFalse
// We do not check for more generalized and trees as we should canonicalize
// to the form above in instcombine. (TODO)
if (!match(U, m_Br(m_And(m_Value(Condition), m_Value(WidenableCondition)),
IfTrueBB, IfFalseBB)))
return false;
if (!match(WidenableCondition,
m_Intrinsic<Intrinsic::experimental_widenable_condition>())) {
if (!match(Condition,
m_Intrinsic<Intrinsic::experimental_widenable_condition>()))
return false;
std::swap(Condition, WidenableCondition);
}
// For the branch to be (easily) widenable, it must not correlate with other
// branches. Thus, the widenable condition must have a single use.
if (!WidenableCondition->hasOneUse() ||
!cast<BranchInst>(U)->getCondition()->hasOneUse())
return false;
// TODO: At the moment, we only recognize the branch if the WC call in this
// specific position. We should generalize!
return match(WidenableCondition,
m_Intrinsic<Intrinsic::experimental_widenable_condition>());
return (WidenableCondition->hasOneUse() &&
cast<BranchInst>(U)->getCondition()->hasOneUse());
}

11
llvm/lib/Transforms/Scalar/GuardWidening.cpp
View File

@ -84,15 +84,16 @@ static Value *getCondition(Instruction *I) {
"Bad guard intrinsic?");
return GI->getArgOperand(0);
}
if (isGuardAsWidenableBranch(I)) {
auto *Cond = cast<BranchInst>(I)->getCondition();
return cast<BinaryOperator>(Cond)->getOperand(0);
}
Value *Cond, *WC;
BasicBlock *IfTrueBB, *IfFalseBB;
if (parseWidenableBranch(I, Cond, WC, IfTrueBB, IfFalseBB))
return Cond;
return cast<BranchInst>(I)->getCondition();
}
// Set the condition for \p I to \p NewCond. \p I can either be a guard or a
// conditional branch.
// conditional branch.
static void setCondition(Instruction *I, Value *NewCond) {
if (IntrinsicInst *GI = dyn_cast<IntrinsicInst>(I)) {
assert(GI->getIntrinsicID() == Intrinsic::experimental_guard &&

50
llvm/lib/Transforms/Utils/GuardUtils.cpp
View File

@ -15,10 +15,12 @@
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
using namespace llvm;
using namespace llvm::PatternMatch;
static cl::opt<uint32_t> PredicatePassBranchWeight(
"guards-predicate-pass-branch-weight", cl::Hidden, cl::init(1 << 20),
@ -80,23 +82,49 @@ void llvm::makeGuardControlFlowExplicit(Function *DeoptIntrinsic,
void llvm::widenWidenableBranch(BranchInst *WidenableBR, Value *NewCond) {
assert(isWidenableBranch(WidenableBR) && "precondition");
Instruction *WCAnd = cast<Instruction>(WidenableBR->getCondition());
// Condition is only guaranteed to dominate branch
WCAnd->moveBefore(WidenableBR);
Value *OldCond = WCAnd->getOperand(0);
IRBuilder<> B(WCAnd);
WCAnd->setOperand(0, B.CreateAnd(NewCond, OldCond));
// The tempting trivially option is to produce something like this:
// br (and oldcond, newcond) where oldcond is assumed to contain a widenable
// condition, but that doesn't match the pattern parseWidenableBranch expects
// so we have to be more sophisticated.
if (match(WidenableBR->getCondition(),
m_Intrinsic<Intrinsic::experimental_widenable_condition>())) {
IRBuilder<> B(WidenableBR);
WidenableBR->setCondition(B.CreateAnd(NewCond,
WidenableBR->getCondition()));
} else {
Instruction *WCAnd = cast<Instruction>(WidenableBR->getCondition());
// Condition is only guaranteed to dominate branch
WCAnd->moveBefore(WidenableBR);
IRBuilder<> B(WCAnd);
const bool Op0IsWC =
match(WCAnd->getOperand(0),
m_Intrinsic<Intrinsic::experimental_widenable_condition>());
const unsigned CondOpIdx = Op0IsWC ? 1 : 0;
Value *OldCond = WCAnd->getOperand(CondOpIdx);
NewCond = B.CreateAnd(NewCond, OldCond);
WCAnd->setOperand(CondOpIdx, NewCond);
}
assert(isWidenableBranch(WidenableBR) && "preserve widenabiliy");
}
void llvm::setWidenableBranchCond(BranchInst *WidenableBR, Value *NewCond) {
assert(isWidenableBranch(WidenableBR) && "precondition");
Instruction *WCAnd = cast<Instruction>(WidenableBR->getCondition());
// Condition is only guaranteed to dominate branch
WCAnd->moveBefore(WidenableBR);
WCAnd->setOperand(0, NewCond);
if (match(WidenableBR->getCondition(),
m_Intrinsic<Intrinsic::experimental_widenable_condition>())) {
IRBuilder<> B(WidenableBR);
WidenableBR->setCondition(B.CreateAnd(NewCond,
WidenableBR->getCondition()));
} else {
Instruction *WCAnd = cast<Instruction>(WidenableBR->getCondition());
// Condition is only guaranteed to dominate branch
WCAnd->moveBefore(WidenableBR);
const bool Op0IsWC =
match(WCAnd->getOperand(0),
m_Intrinsic<Intrinsic::experimental_widenable_condition>());
const unsigned CondOpIdx = Op0IsWC ? 1 : 0;
WCAnd->setOperand(CondOpIdx, NewCond);
}
assert(isWidenableBranch(WidenableBR) && "preserve widenabiliy");
}

85
llvm/test/Transforms/GuardWidening/basic_widenable_condition_guards.ll
View File

@ -1021,6 +1021,91 @@ guarded1: ; preds = %guarded
ret void
}
define void @swapped_wb(i1 %cond_0, i1 %cond_1) {
; CHECK-LABEL: @swapped_wb(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[WIDENABLE_COND:%.*]] = call i1 @llvm.experimental.widenable.condition()
; CHECK-NEXT: [[WIDE_CHK:%.*]] = and i1 [[COND_0:%.*]], [[COND_1:%.*]]
; CHECK-NEXT: [[EXIPLICIT_GUARD_COND:%.*]] = and i1 [[WIDENABLE_COND]], [[WIDE_CHK]]
; CHECK-NEXT: br i1 [[EXIPLICIT_GUARD_COND]], label [[GUARDED:%.*]], label [[DEOPT:%.*]], !prof !0
; CHECK: deopt:
; CHECK-NEXT: call void (...) @llvm.experimental.deoptimize.isVoid() [ "deopt"() ]
; CHECK-NEXT: ret void
; CHECK: guarded:
; CHECK-NEXT: [[WIDENABLE_COND3:%.*]] = call i1 @llvm.experimental.widenable.condition()
; CHECK-NEXT: [[EXIPLICIT_GUARD_COND4:%.*]] = and i1 [[COND_1]], [[WIDENABLE_COND3]]
; CHECK-NEXT: br i1 true, label [[GUARDED1:%.*]], label [[DEOPT2:%.*]], !prof !0
; CHECK: deopt2:
; CHECK-NEXT: call void (...) @llvm.experimental.deoptimize.isVoid() [ "deopt"() ]
; CHECK-NEXT: ret void
; CHECK: guarded1:
; CHECK-NEXT: ret void
;
entry:
%widenable_cond = call i1 @llvm.experimental.widenable.condition()
%exiplicit_guard_cond = and i1 %widenable_cond, %cond_0
br i1 %exiplicit_guard_cond, label %guarded, label %deopt, !prof !0
deopt: ; preds = %entry
call void (...) @llvm.experimental.deoptimize.isVoid() [ "deopt"() ]
ret void
guarded: ; preds = %entry
%widenable_cond3 = call i1 @llvm.experimental.widenable.condition()
%exiplicit_guard_cond4 = and i1 %cond_1, %widenable_cond3
br i1 %exiplicit_guard_cond4, label %guarded1, label %deopt2, !prof !0
deopt2: ; preds = %guarded
call void (...) @llvm.experimental.deoptimize.isVoid() [ "deopt"() ]
ret void
guarded1: ; preds = %guarded
ret void
}
define void @trivial_wb(i1 %cond_0) {
; CHECK-LABEL: @trivial_wb(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[WIDENABLE_COND:%.*]] = call i1 @llvm.experimental.widenable.condition()
; CHECK-NEXT: [[WIDE_CHK:%.*]] = and i1 true, [[COND_0:%.*]]
; CHECK-NEXT: [[TMP0:%.*]] = and i1 [[WIDE_CHK]], [[WIDENABLE_COND]]
; CHECK-NEXT: br i1 [[TMP0]], label [[GUARDED:%.*]], label [[DEOPT:%.*]], !prof !0
; CHECK: deopt:
; CHECK-NEXT: call void (...) @llvm.experimental.deoptimize.isVoid() [ "deopt"() ]
; CHECK-NEXT: ret void
; CHECK: guarded:
; CHECK-NEXT: [[WIDENABLE_COND3:%.*]] = call i1 @llvm.experimental.widenable.condition()
; CHECK-NEXT: [[EXIPLICIT_GUARD_COND4:%.*]] = and i1 [[COND_0]], [[WIDENABLE_COND3]]
; CHECK-NEXT: br i1 true, label [[GUARDED1:%.*]], label [[DEOPT2:%.*]], !prof !0
; CHECK: deopt2:
; CHECK-NEXT: call void (...) @llvm.experimental.deoptimize.isVoid() [ "deopt"() ]
; CHECK-NEXT: ret void
; CHECK: guarded1:
; CHECK-NEXT: ret void
;
entry:
%widenable_cond = call i1 @llvm.experimental.widenable.condition()
br i1 %widenable_cond, label %guarded, label %deopt, !prof !0
deopt: ; preds = %entry
call void (...) @llvm.experimental.deoptimize.isVoid() [ "deopt"() ]
ret void
guarded: ; preds = %entry
%widenable_cond3 = call i1 @llvm.experimental.widenable.condition()
%exiplicit_guard_cond4 = and i1 %cond_0, %widenable_cond3
br i1 %exiplicit_guard_cond4, label %guarded1, label %deopt2, !prof !0
deopt2: ; preds = %guarded
call void (...) @llvm.experimental.deoptimize.isVoid() [ "deopt"() ]
ret void
guarded1: ; preds = %guarded
ret void
}
declare void @llvm.experimental.deoptimize.isVoid(...)
; Function Attrs: inaccessiblememonly nounwind

66
llvm/test/Transforms/LoopPredication/basic_widenable_branch_guards.ll
View File

@ -1924,6 +1924,72 @@ exit: ; preds = %guarded, %entry
ret i32 0
}
define i32 @swapped_wb(i32* %array, i32 %length, i32 %n) {
; CHECK-LABEL: @swapped_wb(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP5:%.*]] = icmp eq i32 [[N:%.*]], 0
; CHECK-NEXT: br i1 [[TMP5]], label [[EXIT:%.*]], label [[LOOP_PREHEADER:%.*]]
; CHECK: loop.preheader:
; CHECK-NEXT: [[WIDENABLE_COND:%.*]] = call i1 @llvm.experimental.widenable.condition()
; CHECK-NEXT: [[TMP0:%.*]] = icmp ule i32 [[N]], [[LENGTH:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i32 0, [[LENGTH]]
; CHECK-NEXT: [[TMP2:%.*]] = and i1 [[TMP1]], [[TMP0]]
; CHECK-NEXT: [[TMP3:%.*]] = and i1 [[TMP2]], [[WIDENABLE_COND]]
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[GUARDED]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT: br i1 [[TMP3]], label [[GUARDED]], label [[DEOPT:%.*]], !prof !0
; CHECK: deopt:
; CHECK-NEXT: [[DEOPTCALL:%.*]] = call i32 (...) @llvm.experimental.deoptimize.i32(i32 9) [ "deopt"() ]
; CHECK-NEXT: ret i32 [[DEOPTCALL]]
; CHECK: guarded:
; CHECK-NEXT: [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT: [[ARRAY_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY:%.*]], i64 [[I_I64]]
; CHECK-NEXT: [[ARRAY_I:%.*]] = load i32, i32* [[ARRAY_I_PTR]], align 4
; CHECK-NEXT: [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC]], [[ARRAY_I]]
; CHECK-NEXT: [[I_NEXT]] = add nuw i32 [[I]], 1
; CHECK-NEXT: [[CONTINUE:%.*]] = icmp ult i32 [[I_NEXT]], [[N]]
; CHECK-NEXT: br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT_LOOPEXIT:%.*]], !prof !1
; CHECK: exit.loopexit:
; CHECK-NEXT: [[LOOP_ACC_NEXT_LCSSA:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED]] ]
; CHECK-NEXT: br label [[EXIT]]
; CHECK: exit:
; CHECK-NEXT: [[RESULT:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[LOOP_ACC_NEXT_LCSSA]], [[EXIT_LOOPEXIT]] ]
; CHECK-NEXT: ret i32 [[RESULT]]
;
entry:
%tmp5 = icmp eq i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader: ; preds = %entry
%widenable_cond = call i1 @llvm.experimental.widenable.condition()
br label %loop
loop: ; preds = %guarded, %loop.preheader
%loop.acc = phi i32 [ %loop.acc.next, %guarded ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %guarded ], [ 0, %loop.preheader ]
%within.bounds = icmp ult i32 %i, %length
%exiplicit_guard_cond = and i1 %widenable_cond, %within.bounds
br i1 %exiplicit_guard_cond, label %guarded, label %deopt, !prof !0
deopt: ; preds = %loop
%deoptcall = call i32 (...) @llvm.experimental.deoptimize.i32(i32 9) [ "deopt"() ]
ret i32 %deoptcall
guarded: ; preds = %loop
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc, %array.i
%i.next = add nuw i32 %i, 1
%continue = icmp ult i32 %i.next, %n
br i1 %continue, label %loop, label %exit, !prof !2
exit: ; preds = %guarded, %entry
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %guarded ]
ret i32 %result
}
declare i32 @llvm.experimental.deoptimize.i32(...)

160
llvm/test/Transforms/LoopPredication/predicate-exits.ll
View File

@ -762,6 +762,166 @@ exit:
ret i32 %result
}
define i32 @swapped_wb(i32* %array, i32 %length, i32 %n, i1 %cond_0) {
; CHECK-LABEL: @swapped_wb(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[WIDENABLE_COND:%.*]] = call i1 @llvm.experimental.widenable.condition()
; CHECK-NEXT: [[TMP0:%.*]] = icmp ugt i32 [[N:%.*]], 1
; CHECK-NEXT: [[UMAX:%.*]] = select i1 [[TMP0]], i32 [[N]], i32 1
; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[UMAX]], -1
; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i32 [[LENGTH:%.*]], [[TMP1]]
; CHECK-NEXT: [[UMIN:%.*]] = select i1 [[TMP2]], i32 [[LENGTH]], i32 [[TMP1]]
; CHECK-NEXT: [[TMP3:%.*]] = icmp ugt i32 [[LENGTH]], [[UMIN]]
; CHECK-NEXT: [[TMP4:%.*]] = freeze i1 [[TMP3]]
; CHECK-NEXT: [[TMP5:%.*]] = and i1 [[TMP4]], [[COND_0:%.*]]
; CHECK-NEXT: [[EXIPLICIT_GUARD_COND:%.*]] = and i1 [[WIDENABLE_COND]], [[TMP5]]
; CHECK-NEXT: br i1 [[EXIPLICIT_GUARD_COND]], label [[LOOP_PREHEADER:%.*]], label [[DEOPT:%.*]], !prof !0
; CHECK: deopt:
; CHECK-NEXT: [[DEOPTRET:%.*]] = call i32 (...) @llvm.experimental.deoptimize.i32() [ "deopt"() ]
; CHECK-NEXT: ret i32 [[DEOPTRET]]
; CHECK: loop.preheader:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[GUARDED]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT: call void @unknown()
; CHECK-NEXT: [[WITHIN_BOUNDS:%.*]] = icmp ult i32 [[I]], [[LENGTH]]
; CHECK-NEXT: br i1 true, label [[GUARDED]], label [[DEOPT2:%.*]], !prof !0
; CHECK: deopt2:
; CHECK-NEXT: call void @unknown()
; CHECK-NEXT: [[DEOPTRET2:%.*]] = call i32 (...) @llvm.experimental.deoptimize.i32() [ "deopt"() ]
; CHECK-NEXT: ret i32 [[DEOPTRET2]]
; CHECK: guarded:
; CHECK-NEXT: [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT: [[ARRAY_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY:%.*]], i64 [[I_I64]]
; CHECK-NEXT: [[ARRAY_I:%.*]] = load i32, i32* [[ARRAY_I_PTR]], align 4
; CHECK-NEXT: store i32 0, i32* [[ARRAY_I_PTR]]
; CHECK-NEXT: [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC]], [[ARRAY_I]]
; CHECK-NEXT: [[I_NEXT]] = add nuw i32 [[I]], 1
; CHECK-NEXT: [[CONTINUE:%.*]] = icmp ult i32 [[I_NEXT]], [[N]]
; CHECK-NEXT: br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK: exit:
; CHECK-NEXT: [[RESULT:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED]] ]
; CHECK-NEXT: ret i32 [[RESULT]]
;
entry:
%widenable_cond = call i1 @llvm.experimental.widenable.condition()
%exiplicit_guard_cond = and i1 %widenable_cond, %cond_0
br i1 %exiplicit_guard_cond, label %loop.preheader, label %deopt, !prof !0
deopt:
%deoptret = call i32 (...) @llvm.experimental.deoptimize.i32() [ "deopt"() ]
ret i32 %deoptret
loop.preheader:
br label %loop
loop:
%loop.acc = phi i32 [ %loop.acc.next, %guarded ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %guarded ], [ 0, %loop.preheader ]
call void @unknown()
%within.bounds = icmp ult i32 %i, %length
br i1 %within.bounds, label %guarded, label %deopt2, !prof !0
deopt2:
call void @unknown()
%deoptret2 = call i32 (...) @llvm.experimental.deoptimize.i32() [ "deopt"() ]
ret i32 %deoptret2
guarded:
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
store i32 0, i32* %array.i.ptr
%loop.acc.next = add i32 %loop.acc, %array.i
%i.next = add nuw i32 %i, 1
%continue = icmp ult i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ %loop.acc.next, %guarded ]
ret i32 %result
}
define i32 @trivial_wb(i32* %array, i32 %length, i32 %n) {
; CHECK-LABEL: @trivial_wb(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = icmp ugt i32 [[N:%.*]], 1
; CHECK-NEXT: [[UMAX:%.*]] = select i1 [[TMP0]], i32 [[N]], i32 1
; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[UMAX]], -1
; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i32 [[LENGTH:%.*]], [[TMP1]]
; CHECK-NEXT: [[UMIN:%.*]] = select i1 [[TMP2]], i32 [[LENGTH]], i32 [[TMP1]]
; CHECK-NEXT: [[TMP3:%.*]] = icmp ugt i32 [[LENGTH]], [[UMIN]]
; CHECK-NEXT: [[TMP4:%.*]] = freeze i1 [[TMP3]]
; CHECK-NEXT: [[WIDENABLE_COND:%.*]] = call i1 @llvm.experimental.widenable.condition()
; CHECK-NEXT: [[TMP5:%.*]] = and i1 [[TMP4]], [[WIDENABLE_COND]]
; CHECK-NEXT: br i1 [[TMP5]], label [[LOOP_PREHEADER:%.*]], label [[DEOPT:%.*]], !prof !0
; CHECK: deopt:
; CHECK-NEXT: [[DEOPTRET:%.*]] = call i32 (...) @llvm.experimental.deoptimize.i32() [ "deopt"() ]
; CHECK-NEXT: ret i32 [[DEOPTRET]]
; CHECK: loop.preheader:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[GUARDED]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT: call void @unknown()
; CHECK-NEXT: [[WITHIN_BOUNDS:%.*]] = icmp ult i32 [[I]], [[LENGTH]]
; CHECK-NEXT: br i1 true, label [[GUARDED]], label [[DEOPT2:%.*]], !prof !0
; CHECK: deopt2:
; CHECK-NEXT: call void @unknown()
; CHECK-NEXT: [[DEOPTRET2:%.*]] = call i32 (...) @llvm.experimental.deoptimize.i32() [ "deopt"() ]
; CHECK-NEXT: ret i32 [[DEOPTRET2]]
; CHECK: guarded:
; CHECK-NEXT: [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT: [[ARRAY_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY:%.*]], i64 [[I_I64]]
; CHECK-NEXT: [[ARRAY_I:%.*]] = load i32, i32* [[ARRAY_I_PTR]], align 4
; CHECK-NEXT: store i32 0, i32* [[ARRAY_I_PTR]]
; CHECK-NEXT: [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC]], [[ARRAY_I]]
; CHECK-NEXT: [[I_NEXT]] = add nuw i32 [[I]], 1
; CHECK-NEXT: [[CONTINUE:%.*]] = icmp ult i32 [[I_NEXT]], [[N]]
; CHECK-NEXT: br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK: exit:
; CHECK-NEXT: [[RESULT:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED]] ]
; CHECK-NEXT: ret i32 [[RESULT]]
;
entry:
%widenable_cond = call i1 @llvm.experimental.widenable.condition()
br i1 %widenable_cond, label %loop.preheader, label %deopt, !prof !0
deopt:
%deoptret = call i32 (...) @llvm.experimental.deoptimize.i32() [ "deopt"() ]
ret i32 %deoptret
loop.preheader:
br label %loop
loop:
%loop.acc = phi i32 [ %loop.acc.next, %guarded ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %guarded ], [ 0, %loop.preheader ]
call void @unknown()
%within.bounds = icmp ult i32 %i, %length
br i1 %within.bounds, label %guarded, label %deopt2, !prof !0
deopt2:
call void @unknown()
%deoptret2 = call i32 (...) @llvm.experimental.deoptimize.i32() [ "deopt"() ]
ret i32 %deoptret2
guarded:
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
store i32 0, i32* %array.i.ptr
%loop.acc.next = add i32 %loop.acc, %array.i
%i.next = add nuw i32 %i, 1
%continue = icmp ult i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ %loop.acc.next, %guarded ]
ret i32 %result
}
; TODO: Non-latch exits can still be predicated
; This is currently prevented by an overly restrictive profitability check.
define i32 @todo_unconditional_latch(i32* %array, i32 %length, i1 %cond_0) {

75
llvm/test/Transforms/SimplifyCFG/wc-widen-block.ll
View File

@ -363,6 +363,81 @@ return:
ret i32 0
}
define i32 @trivial_wb(i1 %cond_0, i32* %p) {
; CHECK-LABEL: @trivial_wb(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[WIDENABLE_COND:%.*]] = call i1 @llvm.experimental.widenable.condition()
; CHECK-NEXT: br i1 [[WIDENABLE_COND]], label [[GUARDED:%.*]], label [[DEOPT:%.*]], !prof !0
; CHECK: deopt:
; CHECK-NEXT: [[DEOPTRET:%.*]] = call i32 (...) @llvm.experimental.deoptimize.i32() [ "deopt"() ]
; CHECK-NEXT: ret i32 [[DEOPTRET]]
; CHECK: guarded:
; CHECK-NEXT: [[V:%.*]] = load i32, i32* [[P:%.*]]
; CHECK-NEXT: [[COND_1:%.*]] = icmp eq i32 [[V]], 0
; CHECK-NEXT: br i1 [[COND_1]], label [[RETURN:%.*]], label [[DEOPT]], !prof !0
; CHECK: return:
; CHECK-NEXT: ret i32 0
;
entry:
%widenable_cond = call i1 @llvm.experimental.widenable.condition()
br i1 %widenable_cond, label %guarded, label %deopt, !prof !0
deopt:
%deoptret = call i32 (...) @llvm.experimental.deoptimize.i32() [ "deopt"() ]
ret i32 %deoptret
guarded:
%v = load i32, i32* %p
%cond_1 = icmp eq i32 %v, 0
br i1 %cond_1, label %return, label %deopt2, !prof !0
deopt2:
%deoptret2 = call i32 (...) @llvm.experimental.deoptimize.i32() [ "deopt"() ]
ret i32 %deoptret2
return:
ret i32 0
}
define i32 @swapped_wb(i1 %cond_0, i32* %p) {
; CHECK-LABEL: @swapped_wb(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[WIDENABLE_COND:%.*]] = call i1 @llvm.experimental.widenable.condition()
; CHECK-NEXT: [[EXIPLICIT_GUARD_COND:%.*]] = and i1 [[WIDENABLE_COND]], [[COND_0:%.*]]
; CHECK-NEXT: br i1 [[EXIPLICIT_GUARD_COND]], label [[GUARDED:%.*]], label [[DEOPT:%.*]], !prof !0
; CHECK: deopt:
; CHECK-NEXT: [[DEOPTRET:%.*]] = call i32 (...) @llvm.experimental.deoptimize.i32() [ "deopt"() ]
; CHECK-NEXT: ret i32 [[DEOPTRET]]
; CHECK: guarded:
; CHECK-NEXT: [[V:%.*]] = load i32, i32* [[P:%.*]]
; CHECK-NEXT: [[COND_1:%.*]] = icmp eq i32 [[V]], 0
; CHECK-NEXT: br i1 [[COND_1]], label [[RETURN:%.*]], label [[DEOPT]], !prof !0
; CHECK: return:
; CHECK-NEXT: ret i32 0
;
entry:
%widenable_cond = call i1 @llvm.experimental.widenable.condition()
%exiplicit_guard_cond = and i1 %widenable_cond, %cond_0
br i1 %exiplicit_guard_cond, label %guarded, label %deopt, !prof !0
deopt:
%deoptret = call i32 (...) @llvm.experimental.deoptimize.i32() [ "deopt"() ]
ret i32 %deoptret
guarded:
%v = load i32, i32* %p
%cond_1 = icmp eq i32 %v, 0
br i1 %cond_1, label %return, label %deopt2, !prof !0
deopt2:
%deoptret2 = call i32 (...) @llvm.experimental.deoptimize.i32() [ "deopt"() ]
ret i32 %deoptret2
return:
ret i32 0
}