From 21f83a2f95c30b21398b6db0f80ac7eb0b4b672a Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Thu, 26 Nov 2009 22:04:42 +0000
Subject: [PATCH] Fix PR5471 by removing an instcombine xform.  Some pieces of
 the code generates store to undef and some generates store to null as the
 idiom for undefined behavior.  Since simplifycfg zaps both, don't remove the
 undefined behavior in instcombine.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89971 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/InstructionCombining.cpp |  6 ------
 test/Transforms/InstCombine/crash.ll           | 12 ++++++++++++
 test/Transforms/InstCombine/store.ll           |  1 +
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 670dd1162bd..f997d60a85e 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -12096,12 +12096,6 @@ Instruction *InstCombiner::visitStoreInst(StoreInst &SI) {
   Value *Val = SI.getOperand(0);
   Value *Ptr = SI.getOperand(1);
 
-  if (isa<UndefValue>(Ptr)) {     // store X, undef -> noop (even if volatile)
-    EraseInstFromFunction(SI);
-    ++NumCombined;
-    return 0;
-  }
-  
   // If the RHS is an alloca with a single use, zapify the store, making the
   // alloca dead.
   // If the RHS is an alloca with a two uses, the other one being a 
diff --git a/test/Transforms/InstCombine/crash.ll b/test/Transforms/InstCombine/crash.ll
index fbac472e197..1528f6ddf3c 100644
--- a/test/Transforms/InstCombine/crash.ll
+++ b/test/Transforms/InstCombine/crash.ll
@@ -125,3 +125,15 @@ l10:
   %v11 = select i1 %v5_, i64 0, i64 %v6
   ret i64 %v11
 }
+
+; PR5471
+define arm_apcscc i32 @test5a() {
+       ret i32 0
+}
+
+define arm_apcscc void @test5() {
+       store i1 true, i1* undef
+       %1 = invoke i32 @test5a() to label %exit unwind label %exit
+exit:
+       ret void
+}
diff --git a/test/Transforms/InstCombine/store.ll b/test/Transforms/InstCombine/store.ll
index 314441eb865..64460d7a6d6 100644
--- a/test/Transforms/InstCombine/store.ll
+++ b/test/Transforms/InstCombine/store.ll
@@ -6,6 +6,7 @@ define void @test1(i32* %P) {
         store i32 124, i32* null
         ret void
 ; CHECK: @test1(
+; CHECK-NEXT: store i32 123, i32* undef
 ; CHECK-NEXT: store i32 undef, i32* null
 ; CHECK-NEXT: ret void
 }