[llvm] r279432 - Revert -r278269 [IndVarSimplify] Eliminate zext of a signed IV when the IV is known to be non-negative
Artur Pilipenko via llvm-commits
llvm-commits at lists.llvm.org
Mon Aug 22 06:12:07 PDT 2016
Author: apilipenko
Date: Mon Aug 22 08:12:07 2016
New Revision: 279432
URL: http://llvm.org/viewvc/llvm-project?rev=279432&view=rev
Log:
Revert -r278269 [IndVarSimplify] Eliminate zext of a signed IV when the IV is known to be non-negative
This change needs to be reverted in order to revert -r278267 which cause performance regression on MultiSource/Benchmarks/TSVC/Symbolics-flt/Symbolics-flt from LNT and some other bechmarks.
See comments on https://reviews.llvm.org/D18777 for details.
Removed:
llvm/trunk/test/Transforms/IndVarSimplify/iv-widen-elim-ext.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp?rev=279432&r1=279431&r2=279432&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp Mon Aug 22 08:12:07 2016
@@ -36,7 +36,6 @@
#include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
-#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Constants.h"
@@ -1290,8 +1289,7 @@ Instruction *WidenIV::widenIVUse(NarrowI
}
}
// Our raison d'etre! Eliminate sign and zero extension.
- if ((isa<SExtInst>(DU.NarrowUse) && (IsSigned || DU.NeverNegative)) ||
- (isa<ZExtInst>(DU.NarrowUse) && (!IsSigned || DU.NeverNegative))) {
+ if (IsSigned ? isa<SExtInst>(DU.NarrowUse) : isa<ZExtInst>(DU.NarrowUse)) {
Value *NewDef = DU.WideDef;
if (DU.NarrowUse->getType() != WideType) {
unsigned CastWidth = SE->getTypeSizeInBits(DU.NarrowUse->getType());
@@ -1380,12 +1378,9 @@ Instruction *WidenIV::widenIVUse(NarrowI
///
void WidenIV::pushNarrowIVUsers(Instruction *NarrowDef, Instruction *WideDef) {
const SCEV *NarrowSCEV = SE->getSCEV(NarrowDef);
- // isKnownPredicate is enough for most cases but still need isKnownNonNegative
- // here to work around conservatism in ScalarEvolution about no-wrap flags.
bool NeverNegative =
SE->isKnownPredicate(ICmpInst::ICMP_SGE, NarrowSCEV,
- SE->getConstant(NarrowSCEV->getType(), 0)) ||
- isKnownNonNegative(NarrowDef, NarrowDef->getModule()->getDataLayout());
+ SE->getConstant(NarrowSCEV->getType(), 0));
for (User *U : NarrowDef->users()) {
Instruction *NarrowUser = cast<Instruction>(U);
Removed: llvm/trunk/test/Transforms/IndVarSimplify/iv-widen-elim-ext.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IndVarSimplify/iv-widen-elim-ext.ll?rev=279431&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/IndVarSimplify/iv-widen-elim-ext.ll (original)
+++ llvm/trunk/test/Transforms/IndVarSimplify/iv-widen-elim-ext.ll (removed)
@@ -1,82 +0,0 @@
-; RUN: opt < %s -indvars -S | FileCheck %s --implicit-check-not sext --implicit-check-not zext
-
-target datalayout = "p:64:64:64-n32:64"
-
-; When widening IV and its users, trunc and zext/sext are not needed
-; if the original 32-bit user is known to be non-negative, whether
-; the IV is considered signed or unsigned.
-define void @foo(i32* %A, i32* %B, i32* %C, i32 %N) {
-; CHECK-LABEL: @foo(
-; CHECK: wide.trip.count = zext
-; CHECK: ret void
-entry:
- %cmp1 = icmp slt i32 0, %N
- br i1 %cmp1, label %for.body.lr.ph, label %for.end
-
-for.body.lr.ph: ; preds = %entry
- br label %for.body
-
-for.body: ; preds = %for.body.lr.ph, %for.inc
- %i.02 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.inc ]
- %idxprom = sext i32 %i.02 to i64
- %arrayidx = getelementptr inbounds i32, i32* %B, i64 %idxprom
- %0 = load i32, i32* %arrayidx, align 4
- %add = add nsw i32 %i.02, 2
- %idxprom1 = zext i32 %add to i64
- %arrayidx2 = getelementptr inbounds i32, i32* %C, i64 %idxprom1
- %1 = load i32, i32* %arrayidx2, align 4
- %add3 = add nsw i32 %0, %1
- %idxprom4 = zext i32 %i.02 to i64
- %arrayidx5 = getelementptr inbounds i32, i32* %A, i64 %idxprom4
- store i32 %add3, i32* %arrayidx5, align 4
- br label %for.inc
-
-for.inc: ; preds = %for.body
- %inc = add nsw i32 %i.02, 1
- %cmp = icmp slt i32 %inc, %N
- br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge
-
-for.cond.for.end_crit_edge: ; preds = %for.inc
- br label %for.end
-
-for.end: ; preds = %for.cond.for.end_crit_edge, %entry
- ret void
-}
-
-define void @foo1(i32* %A, i32* %B, i32* %C, i32 %N) {
-; CHECK-LABEL: @foo1(
-; CHECK: wide.trip.count = zext
-; CHECK: ret void
-entry:
- %cmp1 = icmp slt i32 0, %N
- br i1 %cmp1, label %for.body.lr.ph, label %for.end
-
-for.body.lr.ph: ; preds = %entry
- br label %for.body
-
-for.body: ; preds = %for.body.lr.ph, %for.inc
- %i.02 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.inc ]
- %idxprom = zext i32 %i.02 to i64
- %arrayidx = getelementptr inbounds i32, i32* %B, i64 %idxprom
- %0 = load i32, i32* %arrayidx, align 4
- %add = add nsw i32 %i.02, 2
- %idxprom1 = sext i32 %add to i64
- %arrayidx2 = getelementptr inbounds i32, i32* %C, i64 %idxprom1
- %1 = load i32, i32* %arrayidx2, align 4
- %add3 = add nsw i32 %0, %1
- %idxprom4 = sext i32 %i.02 to i64
- %arrayidx5 = getelementptr inbounds i32, i32* %A, i64 %idxprom4
- store i32 %add3, i32* %arrayidx5, align 4
- br label %for.inc
-
-for.inc: ; preds = %for.body
- %inc = add nsw i32 %i.02, 1
- %cmp = icmp slt i32 %inc, %N
- br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge
-
-for.cond.for.end_crit_edge: ; preds = %for.inc
- br label %for.end
-
-for.end: ; preds = %for.cond.for.end_crit_edge, %entry
- ret void
-}
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