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[RS4GC] Remat in presence of phi and use live value 

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llvm-svn: 282150
This commit is contained in:
Anna Thomas 2016-09-22 13:13:06 +00:00
parent a940e5396b
commit 82c3717f54
2 changed files with 54 additions and 9 deletions
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29
llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
View File

@ -1976,7 +1976,8 @@ static void rematerializeLiveValues(CallSite CS,
// Utility function which clones all instructions from "ChainToBase"
// and inserts them before "InsertBefore". Returns rematerialized value
// which should be used after statepoint.
auto rematerializeChain = [&ChainToBase](Instruction *InsertBefore) {
auto rematerializeChain = [&ChainToBase](
Instruction *InsertBefore, Value *RootOfChain, Value *AlternateLiveBase) {
Instruction *LastClonedValue = nullptr;
Instruction *LastValue = nullptr;
for (Instruction *Instr: ChainToBase) {
@ -1996,13 +1997,24 @@ static void rematerializeLiveValues(CallSite CS,
assert(LastValue);
ClonedValue->replaceUsesOfWith(LastValue, LastClonedValue);
#ifndef NDEBUG
// Assert that cloned instruction does not use any instructions from
// this chain other than LastClonedValue
for (auto OpValue : ClonedValue->operand_values()) {
// Assert that cloned instruction does not use any instructions from
// this chain other than LastClonedValue
assert(!is_contained(ChainToBase, OpValue) &&
"incorrect use in rematerialization chain");
// Assert that the cloned instruction does not use the RootOfChain
// or the AlternateLiveBase.
assert(OpValue != RootOfChain && OpValue != AlternateLiveBase);
}
#endif
} else {
// For the first instruction, replace the use of unrelocated base i.e.
// RootOfChain/OrigRootPhi, with the corresponding PHI present in the
// live set. They have been proved to be the same PHI nodes. Note
// that the *only* use of the RootOfChain in the ChainToBase list is
// the first Value in the list.
if (RootOfChain != AlternateLiveBase)
ClonedValue->replaceUsesOfWith(RootOfChain, AlternateLiveBase);
}
LastClonedValue = ClonedValue;
@ -2017,7 +2029,8 @@ static void rematerializeLiveValues(CallSite CS,
if (CS.isCall()) {
Instruction *InsertBefore = CS.getInstruction()->getNextNode();
assert(InsertBefore);
Instruction *RematerializedValue = rematerializeChain(InsertBefore);
Instruction *RematerializedValue = rematerializeChain(
InsertBefore, RootOfChain, Info.PointerToBase[LiveValue]);
Info.RematerializedValues[RematerializedValue] = LiveValue;
} else {
InvokeInst *Invoke = cast<InvokeInst>(CS.getInstruction());
@ -2027,10 +2040,10 @@ static void rematerializeLiveValues(CallSite CS,
Instruction *UnwindInsertBefore =
&*Invoke->getUnwindDest()->getFirstInsertionPt();
Instruction *NormalRematerializedValue =
rematerializeChain(NormalInsertBefore);
Instruction *UnwindRematerializedValue =
rematerializeChain(UnwindInsertBefore);
Instruction *NormalRematerializedValue = rematerializeChain(
NormalInsertBefore, RootOfChain, Info.PointerToBase[LiveValue]);
Instruction *UnwindRematerializedValue = rematerializeChain(
UnwindInsertBefore, RootOfChain, Info.PointerToBase[LiveValue]);
Info.RematerializedValues[NormalRematerializedValue] = LiveValue;
Info.RematerializedValues[UnwindRematerializedValue] = LiveValue;

34
llvm/test/Transforms/RewriteStatepointsForGC/rematerialize-derived-pointers.ll
View File

@ -285,7 +285,7 @@ merge:
; CHECK: %statepoint_token = call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint
; CHECK: %basephi.base.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %statepoint_token, i32 7, i32 7) ; (%basephi.base, %basephi.base)
; CHECK: %basephi.base.relocated.casted = bitcast i8 addrspace(1)* %basephi.base.relocated to i32 addrspace(1)*
; CHECK: %ptr.gep.remat = getelementptr i32, i32 addrspace(1)* %basephi, i32 15
; CHECK: %ptr.gep.remat = getelementptr i32, i32 addrspace(1)* %basephi.base.relocated.casted, i32 15
; CHECK: call void @use_obj32(i32 addrspace(1)* %ptr.gep.remat)
@ -296,3 +296,35 @@ merge:
call void @use_obj32(i32 addrspace(1)* %ptr.gep)
ret void
}
define void @test_intersecting_chains_with_phi(i1 %cond) gc "statepoint-example" {
; CHECK-LABEL: test_intersecting_chains_with_phi
entry:
%base1 = call i32 addrspace(1)* @new_instance()
%base2 = call i32 addrspace(1)* @new_instance()
br i1 %cond, label %here, label %there
here:
br label %merge
there:
br label %merge
merge:
%basephi = phi i32 addrspace(1)* [ %base1, %here ], [ %base2, %there ]
%ptr.gep = getelementptr i32, i32 addrspace(1)* %basephi, i32 15
%ptr.cast = bitcast i32 addrspace(1)* %ptr.gep to i64 addrspace(1)*
%ptr.cast2 = bitcast i32 addrspace(1)* %ptr.gep to i16 addrspace(1)*
call void @do_safepoint() [ "deopt"() ]
; CHECK: statepoint
; CHECK: %ptr.gep.remat1 = getelementptr i32, i32 addrspace(1)* %basephi.base.relocated.casted, i32 15
; CHECK: %ptr.cast.remat = bitcast i32 addrspace(1)* %ptr.gep.remat1 to i64 addrspace(1)*
; CHECK: %ptr.gep.remat = getelementptr i32, i32 addrspace(1)* %basephi.base.relocated.casted, i32 15
; CHECK: %ptr.cast2.remat = bitcast i32 addrspace(1)* %ptr.gep.remat to i16 addrspace(1)*
; CHECK: call void @use_obj64(i64 addrspace(1)* %ptr.cast.remat)
; CHECK: call void @use_obj16(i16 addrspace(1)* %ptr.cast2.remat)
call void @use_obj64(i64 addrspace(1)* %ptr.cast)
call void @use_obj16(i16 addrspace(1)* %ptr.cast2)
ret void
}