instcombine shouldn't delete all null checks for mallocs.

This fixes PR5130.

llvm-svn: 83290

2 files changed, 21 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
index 561527cbb46..fae8629cde6 100644
--- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -5934,9 +5934,9 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
   
   // icmp <global/alloca*/null>, <global/alloca*/null> - Global/Stack value
   // addresses never equal each other!  We already know that Op0 != Op1.
-  if ((isa<GlobalValue>(Op0) || isa<AllocaInst>(Op0) || isMalloc(Op0) ||
+  if ((isa<GlobalValue>(Op0) || isa<AllocaInst>(Op0) || 
        isa<ConstantPointerNull>(Op0)) &&
-      (isa<GlobalValue>(Op1) || isa<AllocaInst>(Op1) || isMalloc(Op1) ||
+      (isa<GlobalValue>(Op1) || isa<AllocaInst>(Op1) || 
        isa<ConstantPointerNull>(Op1)))
     return ReplaceInstUsesWith(I, ConstantInt::get(Type::getInt1Ty(*Context), 
                                                    !I.isTrueWhenEqual()));
diff --git a/llvm/test/Transforms/InstCombine/badmalloc.ll b/llvm/test/Transforms/InstCombine/badmalloc.ll
new file mode 100644
index 00000000000..cab23b5af59
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/badmalloc.ll
@@ -0,0 +1,19 @@
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+target triple = "x86_64-apple-darwin10.0"
+
+declare noalias i8* @malloc(i64) nounwind
+declare void @free(i8*)
+
+; PR5130
+define i1 @test1() {
+  %A = call noalias i8* @malloc(i64 4) nounwind
+  %B = icmp eq i8* %A, null
+
+  call void @free(i8* %A)
+  ret i1 %B
+
+; CHECK: @test1
+; CHECK: ret i1 %B
+}