[llvm] r296642 - [GVNHoist] Don't hoist unsafe scalars at -Oz (PR31729)
Hans Wennborg via llvm-commits
llvm-commits at lists.llvm.org
Wed Mar 1 09:15:09 PST 2017
Author: hans
Date: Wed Mar 1 11:15:08 2017
New Revision: 296642
URL: http://llvm.org/viewvc/llvm-project?rev=296642&view=rev
Log:
[GVNHoist] Don't hoist unsafe scalars at -Oz (PR31729)
Based on Aditya Kumar's patch:
Differential Revision: https://reviews.llvm.org/D29092
Added:
llvm/trunk/test/Transforms/GVNHoist/hoist-unsafe-pr31729.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/GVNHoist.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/GVNHoist.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GVNHoist.cpp?rev=296642&r1=296641&r2=296642&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/GVNHoist.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/GVNHoist.cpp Wed Mar 1 11:15:08 2017
@@ -201,15 +201,12 @@ static void combineKnownMetadata(Instruc
class GVNHoist {
public:
GVNHoist(DominatorTree *DT, AliasAnalysis *AA, MemoryDependenceResults *MD,
- MemorySSA *MSSA, bool OptForMinSize)
+ MemorySSA *MSSA)
: DT(DT), AA(AA), MD(MD), MSSA(MSSA),
MSSAUpdater(make_unique<MemorySSAUpdater>(MSSA)),
- OptForMinSize(OptForMinSize), HoistingGeps(OptForMinSize),
- HoistedCtr(0) {
- // Hoist as far as possible when optimizing for code-size.
- if (OptForMinSize)
- MaxNumberOfBBSInPath = -1;
- }
+ HoistingGeps(false),
+ HoistedCtr(0)
+ { }
bool run(Function &F) {
VN.setDomTree(DT);
@@ -255,7 +252,6 @@ private:
MemoryDependenceResults *MD;
MemorySSA *MSSA;
std::unique_ptr<MemorySSAUpdater> MSSAUpdater;
- const bool OptForMinSize;
const bool HoistingGeps;
DenseMap<const Value *, unsigned> DFSNumber;
BBSideEffectsSet BBSideEffects;
@@ -509,11 +505,6 @@ private:
bool safeToHoistScalar(const BasicBlock *HoistBB,
SmallPtrSetImpl<const BasicBlock *> &WL,
int &NBBsOnAllPaths) {
- // Enable scalar hoisting at -Oz as it is safe to hoist scalars to a place
- // where they are partially needed.
- if (OptForMinSize)
- return true;
-
// Check that the hoisted expression is needed on all paths.
if (!hoistingFromAllPaths(HoistBB, WL))
return false;
@@ -927,13 +918,8 @@ private:
Intr->getIntrinsicID() == Intrinsic::assume)
continue;
}
- if (Call->mayHaveSideEffects()) {
- if (!OptForMinSize)
- break;
- // We may continue hoisting across calls which write to memory.
- if (Call->mayThrow())
- break;
- }
+ if (Call->mayHaveSideEffects())
+ break;
if (Call->isConvergent())
break;
@@ -975,7 +961,7 @@ public:
auto &MD = getAnalysis<MemoryDependenceWrapperPass>().getMemDep();
auto &MSSA = getAnalysis<MemorySSAWrapperPass>().getMSSA();
- GVNHoist G(&DT, &AA, &MD, &MSSA, F.optForMinSize());
+ GVNHoist G(&DT, &AA, &MD, &MSSA);
return G.run(F);
}
@@ -995,7 +981,7 @@ PreservedAnalyses GVNHoistPass::run(Func
AliasAnalysis &AA = AM.getResult<AAManager>(F);
MemoryDependenceResults &MD = AM.getResult<MemoryDependenceAnalysis>(F);
MemorySSA &MSSA = AM.getResult<MemorySSAAnalysis>(F).getMSSA();
- GVNHoist G(&DT, &AA, &MD, &MSSA, F.optForMinSize());
+ GVNHoist G(&DT, &AA, &MD, &MSSA);
if (!G.run(F))
return PreservedAnalyses::all();
Added: llvm/trunk/test/Transforms/GVNHoist/hoist-unsafe-pr31729.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVNHoist/hoist-unsafe-pr31729.ll?rev=296642&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/GVNHoist/hoist-unsafe-pr31729.ll (added)
+++ llvm/trunk/test/Transforms/GVNHoist/hoist-unsafe-pr31729.ll Wed Mar 1 11:15:08 2017
@@ -0,0 +1,81 @@
+; RUN: opt -gvn-hoist -S < %s | FileCheck %s
+
+; Check that urem is not hoisted.
+; CHECK-LABEL: @main
+; CHECK: urem
+; CHECK: urem
+; CHECK: urem
+
+ at g_x_s = global i32 -470211272, align 4
+ at g_z_s = global i32 2007237709, align 4
+ at g_x_u = global i32 282475249, align 4
+ at g_z_u = global i32 984943658, align 4
+ at g_m = global i32 16807, align 4
+ at res = common global i32 0, align 4
+
+; Function Attrs:
+define i64 @func() #0 {
+entry:
+ ret i64 1
+}
+
+; Function Attrs:
+define i32 @main() {
+entry:
+ %0 = load volatile i32, i32* @g_x_s, align 4
+ %1 = load volatile i32, i32* @g_z_s, align 4
+ %2 = load volatile i32, i32* @g_x_u, align 4
+ %3 = load volatile i32, i32* @g_z_u, align 4
+ %4 = load volatile i32, i32* @g_m, align 4
+ %call = call i64 @func() #4
+ %conv = sext i32 %1 to i64
+ %cmp = icmp ne i64 %call, %conv
+ br i1 %cmp, label %if.end, label %lor.lhs.false
+
+lor.lhs.false:
+ %div = udiv i32 %4, %1
+ %rem = urem i32 %0, %div
+ %cmp2 = icmp eq i32 %rem, 0
+ br i1 %cmp2, label %if.end, label %if.then
+
+if.then:
+ br label %cleanup
+
+if.end:
+ %call4 = call i64 @func() #4
+ %conv5 = zext i32 %3 to i64
+ %cmp6 = icmp ne i64 %call4, %conv5
+ br i1 %cmp6, label %if.end14, label %lor.lhs.false8
+
+lor.lhs.false8:
+ %div9 = udiv i32 %4, %3
+ %rem10 = urem i32 %0, %div9
+ %cmp11 = icmp eq i32 %rem10, 0
+ br i1 %cmp11, label %if.end14, label %if.then13
+
+if.then13:
+ br label %cleanup
+
+if.end14:
+ %call15 = call i64 @func() #4
+ %cmp17 = icmp ne i64 %call15, %conv
+ br i1 %cmp17, label %if.end25, label %lor.lhs.false19
+
+lor.lhs.false19:
+ %div20 = udiv i32 %4, %1
+ %rem21 = urem i32 %0, %div20
+ %cmp22 = icmp eq i32 %rem21, 0
+ br i1 %cmp22, label %if.end25, label %if.then24
+
+if.then24:
+ br label %cleanup
+
+if.end25:
+ br label %cleanup
+
+cleanup:
+ %retval.0 = phi i32 [ 0, %if.end25 ], [ 1, %if.then24 ], [ 1, %if.then13 ], [ 1, %if.then ]
+ ret i32 %retval.0
+}
+
+attributes #0 = { minsize noinline nounwind optsize uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
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