[llvm] r229495 - Fixed a bug in store sinking.
Hal Finkel
hfinkel at anl.gov
Tue Feb 17 11:25:09 PST 2015
Hans,
I'm not sure who the code owner is here, but this fixes a miscompile (PR22613), and we might consider this for the release branch.
-Hal
----- Original Message -----
> From: "Elena Demikhovsky" <elena.demikhovsky at intel.com>
> To: llvm-commits at cs.uiuc.edu
> Sent: Tuesday, February 17, 2015 7:10:05 AM
> Subject: [llvm] r229495 - Fixed a bug in store sinking.
>
> Author: delena
> Date: Tue Feb 17 07:10:05 2015
> New Revision: 229495
>
> URL: http://llvm.org/viewvc/llvm-project?rev=229495&view=rev
> Log:
> Fixed a bug in store sinking.
> The problem was in store-sink barrier check.
>
> Store sink barrier should be checked for ModRef (read-write) mode.
>
> http://llvm.org/bugs/show_bug.cgi?id=22613
>
>
> Added:
> llvm/trunk/test/Transforms/InstMerge/st_sink_bugfix_22613.ll
> Modified:
> llvm/trunk/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp
>
> Modified: llvm/trunk/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp?rev=229495&r1=229494&r2=229495&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp
> (original)
> +++ llvm/trunk/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp Tue
> Feb 17 07:10:05 2015
> @@ -403,7 +403,7 @@ bool MergedLoadStoreMotion::isStoreSinkB
> const
> Instruction&
> End,
> AliasAnalysis::Location
> Loc) {
> - return AA->canInstructionRangeModRef(Start, End, Loc,
> AliasAnalysis::Ref);
> + return AA->canInstructionRangeModRef(Start, End, Loc,
> AliasAnalysis::ModRef);
> }
>
> ///
> @@ -414,6 +414,7 @@ bool MergedLoadStoreMotion::isStoreSinkB
> StoreInst *MergedLoadStoreMotion::canSinkFromBlock(BasicBlock *BB1,
> StoreInst
> *Store0) {
> DEBUG(dbgs() << "can Sink? : "; Store0->dump(); dbgs() << "\n");
> + BasicBlock *BB0 = Store0->getParent();
> for (BasicBlock::reverse_iterator RBI = BB1->rbegin(), RBE =
> BB1->rend();
> RBI != RBE; ++RBI) {
> Instruction *Inst = &*RBI;
> @@ -422,13 +423,14 @@ StoreInst *MergedLoadStoreMotion::canSin
> continue;
>
> StoreInst *Store1 = cast<StoreInst>(Inst);
> - BasicBlock *BB0 = Store0->getParent();
>
> AliasAnalysis::Location Loc0 = AA->getLocation(Store0);
> AliasAnalysis::Location Loc1 = AA->getLocation(Store1);
> if (AA->isMustAlias(Loc0, Loc1) &&
> Store0->isSameOperationAs(Store1) &&
> - !isStoreSinkBarrierInRange(*Store1, BB1->back(), Loc1) &&
> - !isStoreSinkBarrierInRange(*Store0, BB0->back(), Loc0)) {
> +
> !isStoreSinkBarrierInRange(*(std::next(BasicBlock::iterator(Store1))),
> + BB1->back(), Loc1) &&
> +
> !isStoreSinkBarrierInRange(*(std::next(BasicBlock::iterator(Store0))),
> + BB0->back(), Loc0)) {
> return Store1;
> }
> }
>
> Added: llvm/trunk/test/Transforms/InstMerge/st_sink_bugfix_22613.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstMerge/st_sink_bugfix_22613.ll?rev=229495&view=auto
> ==============================================================================
> --- llvm/trunk/test/Transforms/InstMerge/st_sink_bugfix_22613.ll
> (added)
> +++ llvm/trunk/test/Transforms/InstMerge/st_sink_bugfix_22613.ll Tue
> Feb 17 07:10:05 2015
> @@ -0,0 +1,114 @@
> +; ModuleID = 'bug.c'
> +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
> +target triple = "x86_64-unknown-linux-gnu"
> +
> +; RUN: opt -O2 -S < %s | FileCheck %s
> +
> +; CHECK_LABEL: main
> +; CHECK: if.end
> +; CHECK: store
> +; CHECK: memset
> +; CHECK: if.then
> +; CHECK: store
> +; CHECK: memset
> +
> + at d = common global i32 0, align 4
> + at b = common global i32 0, align 4
> + at f = common global [1 x [3 x i8]] zeroinitializer, align 1
> + at e = common global i32 0, align 4
> + at c = common global i32 0, align 4
> + at a = common global i32 0, align 4
> +
> +; Function Attrs: nounwind uwtable
> +define void @fn1() #0 {
> +entry:
> + store i32 0, i32* @d, align 4
> + br label %for.cond
> +
> +for.cond: ; preds =
> %for.inc8, %entry
> + %0 = load i32* @d, align 4
> + %cmp = icmp slt i32 %0, 2
> + br i1 %cmp, label %for.body, label %for.end10
> +
> +for.body: ; preds =
> %for.cond
> + %1 = load i32* @d, align 4
> + %idxprom = sext i32 %1 to i64
> + %2 = load i32* @b, align 4
> + %idxprom1 = sext i32 %2 to i64
> + %arrayidx = getelementptr inbounds [1 x [3 x i8]]* @f, i32 0, i64
> %idxprom1
> + %arrayidx2 = getelementptr inbounds [3 x i8]* %arrayidx, i32 0,
> i64 %idxprom
> + store i8 0, i8* %arrayidx2, align 1
> + store i32 0, i32* @e, align 4
> + br label %for.cond3
> +
> +for.cond3: ; preds =
> %for.inc, %for.body
> + %3 = load i32* @e, align 4
> + %cmp4 = icmp slt i32 %3, 3
> + br i1 %cmp4, label %for.body5, label %for.end
> +
> +for.body5: ; preds =
> %for.cond3
> + %4 = load i32* @c, align 4
> + %tobool = icmp ne i32 %4, 0
> + br i1 %tobool, label %if.then, label %if.end
> +
> +if.then: ; preds =
> %for.body5
> + %5 = load i32* @a, align 4
> + %dec = add nsw i32 %5, -1
> + store i32 %dec, i32* @a, align 4
> + br label %if.end
> +
> +if.end: ; preds =
> %if.then, %for.body5
> + %6 = load i32* @e, align 4
> + %idxprom6 = sext i32 %6 to i64
> + %arrayidx7 = getelementptr inbounds [3 x i8]* getelementptr
> inbounds ([1 x [3 x i8]]* @f, i32 0, i64 0), i32 0, i64 %idxprom6
> + store i8 1, i8* %arrayidx7, align 1
> + br label %for.inc
> +
> +for.inc: ; preds = %if.end
> + %7 = load i32* @e, align 4
> + %inc = add nsw i32 %7, 1
> + store i32 %inc, i32* @e, align 4
> + br label %for.cond3
> +
> +for.end: ; preds =
> %for.cond3
> + br label %for.inc8
> +
> +for.inc8: ; preds = %for.end
> + %8 = load i32* @d, align 4
> + %inc9 = add nsw i32 %8, 1
> + store i32 %inc9, i32* @d, align 4
> + br label %for.cond
> +
> +for.end10: ; preds =
> %for.cond
> + ret void
> +}
> +
> +; Function Attrs: nounwind uwtable
> +define i32 @main() #0 {
> +entry:
> + %retval = alloca i32, align 4
> + store i32 0, i32* %retval
> + call void @fn1()
> + %0 = load i8* getelementptr inbounds ([1 x [3 x i8]]* @f, i32 0,
> i64 0, i64 1), align 1
> + %conv = sext i8 %0 to i32
> + %cmp = icmp ne i32 %conv, 1
> + br i1 %cmp, label %if.then, label %if.end
> +
> +if.then: ; preds = %entry
> + call void @abort() #2
> + unreachable
> +
> +if.end: ; preds = %entry
> + ret i32 0
> +}
> +
> +; Function Attrs: noreturn nounwind
> +declare void @abort() #1
> +
> +attributes #0 = { nounwind uwtable "less-precise-fpmad"="false"
> "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"
> "no-infs-fp-math"="false" "no-nans-fp-math"="false"
> "stack-protector-buffer-size"="8" "unsafe-fp-math"="false"
> "use-soft-float"="false" }
> +attributes #1 = { noreturn nounwind "less-precise-fpmad"="false"
> "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"
> "no-infs-fp-math"="false" "no-nans-fp-math"="false"
> "stack-protector-buffer-size"="8" "unsafe-fp-math"="false"
> "use-soft-float"="false" }
> +attributes #2 = { noreturn nounwind }
> +
> +!llvm.ident = !{!0}
> +
> +!0 = !{!"clang version 3.7.0 (trunk 229288) (llvm/trunk
> 229286:229290M)"}
>
>
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>
--
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory
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