GlobalOpt: non-constexpr bitcasts or GEPs can occur even if the global value is only...

Fixes PR13968.

llvm-svn: 164815

diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
index b888e95..b1ba6be 100644 (file)
--- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -962,7 +962,9 @@ static bool OptimizeAwayTrappingUsesOfLoads(GlobalVariable *GV, Constant *LV,
       // If we get here we could have other crazy uses that are transitively
       // loaded.
       assert((isa<PHINode>(GlobalUser) || isa<SelectInst>(GlobalUser) ||
-              isa<ConstantExpr>(GlobalUser) || isa<CmpInst>(GlobalUser)) &&
+              isa<ConstantExpr>(GlobalUser) || isa<CmpInst>(GlobalUser) ||
+              isa<BitCastInst>(GlobalUser) ||
+              isa<GetElementPtrInst>(GlobalUser)) &&
              "Only expect load and stores!");
     }
   }

diff --git a/llvm/test/Transforms/GlobalOpt/load-store-global.ll b/llvm/test/Transforms/GlobalOpt/load-store-global.ll
index f824b2c..25a5337 100644 (file)
--- a/llvm/test/Transforms/GlobalOpt/load-store-global.ll
+++ b/llvm/test/Transforms/GlobalOpt/load-store-global.ll
@@ -1,15 +1,38 @@
-; RUN: opt < %s -globalopt -S | not grep G
+; RUN: opt < %s -globalopt -S | FileCheck %s
 
 @G = internal global i32 17             ; <i32*> [#uses=3]
+; CHECK-NOT: @G
 
 define void @foo() {
         %V = load i32* @G               ; <i32> [#uses=1]
         store i32 %V, i32* @G
         ret void
+; CHECK: @foo
+; CHECK-NEXT: ret void
 }
 
 define i32 @bar() {
         %X = load i32* @G               ; <i32> [#uses=1]
         ret i32 %X
+; CHECK: @bar
+; CHECK-NEXT: ret i32 17
+}
+
+@a = internal global i64* null, align 8
+; CHECK-NOT: @a
+
+; PR13968
+define void @qux() nounwind {
+  %b = bitcast i64** @a to i8*
+  %g = getelementptr i64** @a, i32 1
+  %cmp = icmp ne i8* null, %b
+  %cmp2 = icmp eq i8* null, %b
+  %cmp3 = icmp eq i64** null, %g
+  store i64* inttoptr (i64 1 to i64*), i64** @a, align 8
+  %l = load i64** @a, align 8
+  ret void
+; CHECK: @qux
+; CHECK-NOT: store
+; CHECK-NOT: load
 }