[llvm] r299823 - [MemorySSA] Fix use of pointsToConstantMemory in isUseTriviallyOptimizableToLiveOnEntry

[Hal Finkel via llvm-commits]

Author: hfinkel
Date: Sun Apr  9 07:57:50 2017
New Revision: 299823

URL: http://llvm.org/viewvc/llvm-project?rev=299823&view=rev
Log:
[MemorySSA] Fix use of pointsToConstantMemory in isUseTriviallyOptimizableToLiveOnEntry

In isUseTriviallyOptimizableToLiveOnEntry, pointsToConstantMemory needs to be
called on the load's pointer operand, not on the result of the load (which
might not even be a pointer).

Added:
    llvm/trunk/test/Transforms/Util/MemorySSA/ptr-const-mem.ll
Modified:
    llvm/trunk/lib/Transforms/Utils/MemorySSA.cpp

Modified: llvm/trunk/lib/Transforms/Utils/MemorySSA.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/MemorySSA.cpp?rev=299823&r1=299822&r2=299823&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/MemorySSA.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/MemorySSA.cpp Sun Apr  9 07:57:50 2017
@@ -316,7 +316,8 @@ static bool isUseTriviallyOptimizableToL
   // FIXME: We should handle invariant groups, as well. It's a bit harder,
   // because we need to pay close attention to invariant group barriers.
   return isa<LoadInst>(I) && (I->getMetadata(LLVMContext::MD_invariant_load) ||
-                              AA.pointsToConstantMemory(I));
+                              AA.pointsToConstantMemory(cast<LoadInst>(I)->
+                                                          getPointerOperand()));
 }
 
 /// Verifies that `Start` is clobbered by `ClobberAt`, and that nothing

Added: llvm/trunk/test/Transforms/Util/MemorySSA/ptr-const-mem.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Util/MemorySSA/ptr-const-mem.ll?rev=299823&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/Util/MemorySSA/ptr-const-mem.ll (added)
+++ llvm/trunk/test/Transforms/Util/MemorySSA/ptr-const-mem.ll Sun Apr  9 07:57:50 2017
@@ -0,0 +1,23 @@
+; RUN: opt -basicaa -print-memoryssa -verify-memoryssa -analyze -memssa-check-limit=0 < %s 2>&1 | FileCheck %s
+; RUN: opt -aa-pipeline=basic-aa -passes='print<memoryssa>' -verify-memoryssa -disable-output -memssa-check-limit=0 < %s 2>&1 | FileCheck %s
+target datalayout = "e-p:32:32-p1:64:64-p2:64:64-p3:32:32-p4:64:64-p5:32:32-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64"
+target triple = "amdgcn"
+
+ at g4 = external unnamed_addr constant i8, align 1
+
+define signext i8 @cmp_constant(i8* %q, i8 %v) local_unnamed_addr {
+entry:
+
+  store i8 %v, i8* %q, align 1
+; CHECK: 1 = MemoryDef(liveOnEntry)
+; CHECK-NEXT: store i8 %v, i8* %q, align 1
+
+  %0 = load i8, i8* @g4, align 1
+; Make sure that this load is liveOnEntry just based on the fact that @g4 is
+; constant memory.
+; CHECK: MemoryUse(liveOnEntry)
+; CHECK-NEXT: load i8, i8* @g4, align 1
+
+  ret i8 %0
+}
+