[llvm-commits] [llvm] r137690 - in /llvm/trunk: lib/Transforms/Utils/PromoteMemoryToRegister.cpp test/Transforms/Mem2Reg/atomic.ll

[Eli Friedman]

Author: efriedma
Date: Mon Aug 15 18:55:52 2011
New Revision: 137690

URL: http://llvm.org/viewvc/llvm-project?rev=137690&view=rev
Log:
Add comments and test for atomic load/store and mem2reg.


Added:
    llvm/trunk/test/Transforms/Mem2Reg/atomic.ll
Modified:
    llvm/trunk/lib/Transforms/Utils/PromoteMemoryToRegister.cpp

Modified: llvm/trunk/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/PromoteMemoryToRegister.cpp?rev=137690&r1=137689&r2=137690&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/PromoteMemoryToRegister.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/PromoteMemoryToRegister.cpp Mon Aug 15 18:55:52 2011
@@ -86,11 +86,15 @@
        UI != UE; ++UI) {   // Loop over all of the uses of the alloca
     const User *U = *UI;
     if (const LoadInst *LI = dyn_cast<LoadInst>(U)) {
+      // Note that atomic loads can be transformed; atomic semantics do
+      // not have any meaning for a local alloca.
       if (LI->isVolatile())
         return false;
     } else if (const StoreInst *SI = dyn_cast<StoreInst>(U)) {
       if (SI->getOperand(0) == AI)
         return false;   // Don't allow a store OF the AI, only INTO the AI.
+      // Note that atomic stores can be transformed; atomic semantics do
+      // not have any meaning for a local alloca.
       if (SI->isVolatile())
         return false;
     } else if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(U)) {

Added: llvm/trunk/test/Transforms/Mem2Reg/atomic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Mem2Reg/atomic.ll?rev=137690&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/Mem2Reg/atomic.ll (added)
+++ llvm/trunk/test/Transforms/Mem2Reg/atomic.ll Mon Aug 15 18:55:52 2011
@@ -0,0 +1,12 @@
+; RUN: opt -mem2reg < %s -S | FileCheck %s
+
+; mem2reg is allowed with arbitrary atomic operations (although we only support
+; it for atomic load and store at the moment).
+define i32 @test1(i32 %x) {
+; CHECK: @test1
+; CHECK: ret i32 %x
+  %a = alloca i32
+  store atomic i32 %x, i32* %a seq_cst, align 4
+  %r = load atomic i32* %a seq_cst, align 4
+  ret i32 %r
+}