Don't remove side effecting instructions due to ConstantFoldInstruction

Just because we can constant fold the result of an instruction does not
imply that we can delete the instruction.  It may have side effects.

This fixes PR28655.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276389 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 310c292..99b12d4 100644 (file)
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -44,6 +44,7 @@
 #include "llvm/Transforms/Utils/CtorUtils.h"
 #include "llvm/Transforms/Utils/Evaluator.h"
 #include "llvm/Transforms/Utils/GlobalStatus.h"
+#include "llvm/Transforms/Utils/Local.h"
 #include <algorithm>
 using namespace llvm;
 
@@ -779,7 +780,8 @@ static void ConstantPropUsersOf(Value *V, const DataLayout &DL,
         // Instructions could multiply use V.
         while (UI != E && *UI == I)
           ++UI;
-        I->eraseFromParent();
+        if (isInstructionTriviallyDead(I, TLI))
+          I->eraseFromParent();
       }
 }
 

diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index 51c3262..377ccb9 100644 (file)
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2830,7 +2830,8 @@ bool InstCombiner::run() {
         // Add operands to the worklist.
         replaceInstUsesWith(*I, C);
         ++NumConstProp;
-        eraseInstFromFunction(*I);
+        if (isInstructionTriviallyDead(I, TLI))
+          eraseInstFromFunction(*I);
         MadeIRChange = true;
         continue;
       }
@@ -2851,7 +2852,8 @@ bool InstCombiner::run() {
         // Add operands to the worklist.
         replaceInstUsesWith(*I, C);
         ++NumConstProp;
-        eraseInstFromFunction(*I);
+        if (isInstructionTriviallyDead(I, TLI))
+          eraseInstFromFunction(*I);
         MadeIRChange = true;
         continue;
       }
@@ -3007,7 +3009,8 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB, const DataLayout &DL,
                        << *Inst << '\n');
           Inst->replaceAllUsesWith(C);
           ++NumConstProp;
-          Inst->eraseFromParent();
+          if (isInstructionTriviallyDead(Inst, TLI))
+            Inst->eraseFromParent();
           continue;
         }
 

diff --git a/lib/Transforms/Scalar/ConstantProp.cpp b/lib/Transforms/Scalar/ConstantProp.cpp
index 88172d1..9e98219 100644 (file)
--- a/lib/Transforms/Scalar/ConstantProp.cpp
+++ b/lib/Transforms/Scalar/ConstantProp.cpp
@@ -19,6 +19,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/Local.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/IR/Constant.h"
@@ -90,11 +91,13 @@ bool ConstantPropagation::runOnFunction(Function &F) {
 
         // Remove the dead instruction.
         WorkList.erase(I);
-        I->eraseFromParent();
+        if (isInstructionTriviallyDead(I, TLI)) {
+          I->eraseFromParent();
+          ++NumInstKilled;
+        }
 
         // We made a change to the function...
         Changed = true;
-        ++NumInstKilled;
       }
   }
   return Changed;

diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp
index b9e717c..d1769fc 100644 (file)
--- a/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/lib/Transforms/Scalar/JumpThreading.cpp
@@ -758,7 +758,8 @@ bool JumpThreadingPass::ProcessBlock(BasicBlock *BB) {
         ConstantFoldInstruction(I, BB->getModule()->getDataLayout(), TLI);
     if (SimpleVal) {
       I->replaceAllUsesWith(SimpleVal);
-      I->eraseFromParent();
+      if (isInstructionTriviallyDead(I, TLI))
+        I->eraseFromParent();
       Condition = SimpleVal;
     }
   }

diff --git a/lib/Transforms/Scalar/LICM.cpp b/lib/Transforms/Scalar/LICM.cpp
index 2c0a70e..cdd17fc 100644 (file)
--- a/lib/Transforms/Scalar/LICM.cpp
+++ b/lib/Transforms/Scalar/LICM.cpp
@@ -377,9 +377,11 @@ bool llvm::hoistRegion(DomTreeNode *N, AliasAnalysis *AA, LoopInfo *LI,
               &I, I.getModule()->getDataLayout(), TLI)) {
         DEBUG(dbgs() << "LICM folding inst: " << I << "  --> " << *C << '\n');
         CurAST->copyValue(&I, C);
-        CurAST->deleteValue(&I);
         I.replaceAllUsesWith(C);
-        I.eraseFromParent();
+        if (isInstructionTriviallyDead(&I, TLI)) {
+          CurAST->deleteValue(&I);
+          I.eraseFromParent();
+        }
         continue;
       }
 

diff --git a/test/Transforms/ConstProp/calls.ll b/test/Transforms/ConstProp/calls.ll
index 736d8c1..d9a884a 100644 (file)
--- a/test/Transforms/ConstProp/calls.ll
+++ b/test/Transforms/ConstProp/calls.ll
@@ -1,47 +1,47 @@
 ; RUN: opt < %s -constprop -S | FileCheck %s
 ; RUN: opt < %s -constprop -disable-simplify-libcalls -S | FileCheck %s --check-prefix=FNOBUILTIN
 
-declare double @acos(double)
-declare double @asin(double)
-declare double @atan(double)
-declare double @atan2(double, double)
-declare double @ceil(double)
-declare double @cos(double)
-declare double @cosh(double)
-declare double @exp(double)
-declare double @exp2(double)
-declare double @fabs(double)
-declare double @floor(double)
-declare double @fmod(double, double)
-declare double @log(double)
-declare double @log10(double)
-declare double @pow(double, double)
-declare double @sin(double)
-declare double @sinh(double)
-declare double @sqrt(double)
-declare double @tan(double)
-declare double @tanh(double)
+declare double @acos(double) readnone nounwind
+declare double @asin(double) readnone nounwind
+declare double @atan(double) readnone nounwind
+declare double @atan2(double, double) readnone nounwind
+declare double @ceil(double) readnone nounwind
+declare double @cos(double) readnone nounwind
+declare double @cosh(double) readnone nounwind
+declare double @exp(double) readnone nounwind
+declare double @exp2(double) readnone nounwind
+declare double @fabs(double) readnone nounwind
+declare double @floor(double) readnone nounwind
+declare double @fmod(double, double) readnone nounwind
+declare double @log(double) readnone nounwind
+declare double @log10(double) readnone nounwind
+declare double @pow(double, double) readnone nounwind
+declare double @sin(double) readnone nounwind
+declare double @sinh(double) readnone nounwind
+declare double @sqrt(double) readnone nounwind
+declare double @tan(double) readnone nounwind
+declare double @tanh(double) readnone nounwind
 
-declare float @acosf(float)
-declare float @asinf(float)
-declare float @atanf(float)
-declare float @atan2f(float, float)
-declare float @ceilf(float)
-declare float @cosf(float)
-declare float @coshf(float)
-declare float @expf(float)
-declare float @exp2f(float)
-declare float @fabsf(float)
-declare float @floorf(float)
-declare float @fmodf(float, float)
-declare float @logf(float)
-declare float @log10f(float)
-declare float @powf(float, float)
-declare float @sinf(float)
-declare float @sinhf(float)
-declare float @sqrtf(float)
-declare float @tanf(float)
-declare float @tanhf(float)
+declare float @acosf(float) readnone nounwind
+declare float @asinf(float) readnone nounwind
+declare float @atanf(float) readnone nounwind
+declare float @atan2f(float, float) readnone nounwind
+declare float @ceilf(float) readnone nounwind
+declare float @cosf(float) readnone nounwind
+declare float @coshf(float) readnone nounwind
+declare float @expf(float) readnone nounwind
+declare float @exp2f(float) readnone nounwind
+declare float @fabsf(float) readnone nounwind
+declare float @floorf(float) readnone nounwind
+declare float @fmodf(float, float) readnone nounwind
+declare float @logf(float) readnone nounwind
+declare float @log10f(float) readnone nounwind
+declare float @powf(float, float) readnone nounwind
+declare float @sinf(float) readnone nounwind
+declare float @sinhf(float) readnone nounwind
+declare float @sqrtf(float) readnone nounwind
+declare float @tanf(float) readnone nounwind
+declare float @tanhf(float) readnone nounwind
 
 define double @T() {
 ; CHECK-LABEL: @T(

diff --git a/test/Transforms/InstCombine/call.ll b/test/Transforms/InstCombine/call.ll
index ea338f0..5307dcb 100644 (file)
--- a/test/Transforms/InstCombine/call.ll
+++ b/test/Transforms/InstCombine/call.ll
@@ -276,3 +276,14 @@ define <2 x i16> @test16() {
   %X = call <2 x i16> bitcast (i32 ()* @test16a to <2 x i16> ()*)( )
   ret <2 x i16> %X
 }
+
+declare i32 @pr28655(i32 returned %V)
+
+define i32 @test17() {
+entry:
+  %C = call i32 @pr28655(i32 0)
+  ret i32 %C
+}
+; CHECK-LABEL: @test17(
+; CHECK: call i32 @pr28655(i32 0)
+; CHECK: ret i32 0

diff --git a/test/Transforms/InstCombine/log-pow.ll b/test/Transforms/InstCombine/log-pow.ll
index a0c10d0..4e4a2b2 100644 (file)
--- a/test/Transforms/InstCombine/log-pow.ll
+++ b/test/Transforms/InstCombine/log-pow.ll
@@ -55,7 +55,8 @@ define double @log_exp2_not_fast(double %x) {
 ; CHECK-NEXT:  %call3 = call fast double @log(double %call2)
 ; CHECK-NEXT:  ret double %call3
 
-declare double @log(double)
+declare double @log(double) #0
 declare double @exp2(double)
 declare double @llvm.pow.f64(double, double)
 
+attributes #0 = { nounwind readnone }