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[CallSiteSplitting] Don't let debug intrinsics affect optimizations

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Summary:
This solves PR35616.

We don't want the compiler to generate different code when we compile
with/without -g, so we now ignore debug intrinsics when determining if
the optimization can trigger or not.

Reviewers: junbuml

Subscribers: davide, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D41068

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320460 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Mikael Holmen 2017-12-12 07:29:57 +00:00
parent d70b230f0a
commit 1aa233defa
2 changed files with 62 additions and 4 deletions
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9
lib/Transforms/Scalar/CallSiteSplitting.cpp
View File

@ -221,7 +221,7 @@ static bool canSplitCallSite(CallSite CS) {
// call instruction, and we do not move a call-site across any other
// instruction.
BasicBlock *CallSiteBB = Instr->getParent();
if (Instr != CallSiteBB->getFirstNonPHI())
if (Instr != CallSiteBB->getFirstNonPHIOrDbg())
return false;
// Need 2 predecessors and cannot split an edge from an IndirectBrInst.
@ -278,7 +278,7 @@ static void splitCallSite(CallSite CS, BasicBlock *PredBB1, BasicBlock *PredBB2,
Instruction *CallInst1, Instruction *CallInst2) {
Instruction *Instr = CS.getInstruction();
BasicBlock *TailBB = Instr->getParent();
assert(Instr == (TailBB->getFirstNonPHI()) && "Unexpected call-site");
assert(Instr == (TailBB->getFirstNonPHIOrDbg()) && "Unexpected call-site");
BasicBlock *SplitBlock1 =
SplitBlockPredecessors(TailBB, PredBB1, ".predBB1.split");
@ -315,7 +315,8 @@ static void splitCallSite(CallSite CS, BasicBlock *PredBB1, BasicBlock *PredBB2,
// Replace users of the original call with a PHI mering call-sites split.
if (Instr->getNumUses()) {
PHINode *PN = PHINode::Create(Instr->getType(), 2, "phi.call", Instr);
PHINode *PN = PHINode::Create(Instr->getType(), 2, "phi.call",
TailBB->getFirstNonPHI());
PN->addIncoming(CallInst1, SplitBlock1);
PN->addIncoming(CallInst2, SplitBlock2);
Instr->replaceAllUsesWith(PN);
@ -334,7 +335,7 @@ static void splitCallSite(CallSite CS, BasicBlock *PredBB1, BasicBlock *PredBB2,
static bool isPredicatedOnPHI(CallSite CS) {
Instruction *Instr = CS.getInstruction();
BasicBlock *Parent = Instr->getParent();
if (Instr != Parent->getFirstNonPHI())
if (Instr != Parent->getFirstNonPHIOrDbg())
return false;
for (auto &BI : *Parent) {

57
test/Transforms/CallSiteSplitting/callsite-split-debug.ll Normal file
View File

@ -0,0 +1,57 @@
; RUN: opt -S -callsite-splitting -o - < %s | FileCheck %s
; RUN: opt -S -strip-debug -callsite-splitting -o - < %s | FileCheck %s
define internal i16 @bar(i16 %p1, i16 %p2) {
%_tmp3 = mul i16 %p2, %p1
ret i16 %_tmp3
}
define i16 @foo(i16 %in) {
bb0:
br label %bb1
bb1:
%0 = icmp ne i16 %in, 0
br i1 %0, label %bb2, label %CallsiteBB
bb2:
br label %CallsiteBB
CallsiteBB:
%1 = phi i16 [ 0, %bb1 ], [ 1, %bb2 ]
%c = phi i16 [ 2, %bb1 ], [ 3, %bb2 ]
call void @llvm.dbg.value(metadata i16 %c, metadata !7, metadata !DIExpression()), !dbg !8
%2 = call i16 @bar(i16 %1, i16 5)
ret i16 %2
}
; Function Attrs: nounwind readnone speculatable
declare void @llvm.dbg.value(metadata, metadata, metadata) #0
attributes #0 = { nounwind readnone speculatable }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!2, !3}
!llvm.ident = !{!4}
!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "My Compiler")
!1 = !DIFile(filename: "foo.c", directory: "/bar")
!2 = !{i32 2, !"Dwarf Version", i32 4}
!3 = !{i32 2, !"Debug Info Version", i32 3}
!4 = !{!"My Compiler"}
!5 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_signed)
!6 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 4, unit: !0)
!7 = !DILocalVariable(name: "c", scope: !6, line: 5, type: !5)
!8 = !DILocation(line: 5, column: 7, scope: !6)
; The optimization should trigger even in the presence of the dbg.value in
; CallSiteBB.
; CHECK-LABEL: @foo
; CHECK-LABEL: CallsiteBB.predBB1.split:
; CHECK: [[TMP1:%[0-9]+]] = call i16 @bar(i16 1, i16 5)
; CHECK-LABEL: CallsiteBB.predBB2.split:
; CHECK: [[TMP2:%[0-9]+]] = call i16 @bar(i16 0, i16 5)
; CHECK-LABEL: CallsiteBB
; CHECK: %phi.call = phi i16 [ [[TMP1]], %CallsiteBB.predBB1.split ], [ [[TMP2]], %CallsiteBB.predBB2.split