From 3f71cf14b224d8c4f5634296ab785e227ba3c03c Mon Sep 17 00:00:00 2001
From: Stepan Dyatkovskiy <stpworld@narod.ru>
Date: Sat, 5 May 2012 07:09:40 +0000
Subject: [PATCH] Small fix in InstCombineCasts.cpp. Restored "alloca +
 bitcast" reducing for case when alloca's size is calculated within the
 "add/sub/... nsw". Also added fix to 2011-06-13-nsw-alloca.ll test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156231 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/InstCombine/InstCombineCasts.cpp      | 2 +-
 test/Transforms/InstCombine/2011-06-13-nsw-alloca.ll | 7 +++++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/lib/Transforms/InstCombine/InstCombineCasts.cpp b/lib/Transforms/InstCombine/InstCombineCasts.cpp
index 39279f43720..d07be2c8b38 100644
--- a/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -34,7 +34,7 @@ static Value *DecomposeSimpleLinearExpr(Value *Val, unsigned &Scale,
   if (BinaryOperator *I = dyn_cast<BinaryOperator>(Val)) {
     // Cannot look past anything that might overflow.
     OverflowingBinaryOperator *OBI = dyn_cast<OverflowingBinaryOperator>(Val);
-    if (OBI && !OBI->hasNoUnsignedWrap()) {
+    if (OBI && !OBI->hasNoUnsignedWrap() && !OBI->hasNoSignedWrap()) {
       Scale = 1;
       Offset = 0;
       return Val;
diff --git a/test/Transforms/InstCombine/2011-06-13-nsw-alloca.ll b/test/Transforms/InstCombine/2011-06-13-nsw-alloca.ll
index 2f72b73801d..fedb46dd24a 100644
--- a/test/Transforms/InstCombine/2011-06-13-nsw-alloca.ll
+++ b/test/Transforms/InstCombine/2011-06-13-nsw-alloca.ll
@@ -2,8 +2,10 @@
 target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32"
 target triple = "i386-apple-darwin10.0.0"
 
+; CHECK: define void @fu1
 define void @fu1(i32 %parm) nounwind ssp {
   %1 = alloca i32, align 4
+; CHECK: alloca double*
   %ptr = alloca double*, align 4
   store i32 %parm, i32* %1, align 4
   store double* null, double** %ptr, align 4
@@ -16,12 +18,12 @@ define void @fu1(i32 %parm) nounwind ssp {
   %6 = mul nsw i32 %5, 8
 ; With "nsw", the alloca and its bitcast can be fused:
   %7 = add nsw i32 %6, 2048
-; CHECK: alloca double*
+;  CHECK: alloca double
   %8 = alloca i8, i32 %7
   %9 = bitcast i8* %8 to double*
+; CHECK-NEXT: store double*
   store double* %9, double** %ptr, align 4
   br label %10
-
 ; <label>:10                                      ; preds = %4, %0
   %11 = load double** %ptr, align 4
   call void @bar(double* %11)
@@ -31,6 +33,7 @@ define void @fu1(i32 %parm) nounwind ssp {
 
 declare void @bar(double*)
 
+; CHECK: define void @fu2
 define void @fu2(i32 %parm) nounwind ssp {
   %1 = alloca i32, align 4
   %ptr = alloca double*, align 4
-- 
2.11.0