[llvm-commits] [llvm] r120363 - in /llvm/trunk: lib/Transforms/Scalar/DeadStoreElimination.cpp test/Transforms/DeadStoreElimination/simple.ll

[Chris Lattner]

Author: lattner
Date: Mon Nov 29 18:12:39 2010
New Revision: 120363

URL: http://llvm.org/viewvc/llvm-project?rev=120363&view=rev
Log:
my previous patch would cause us to start deleting some volatile
stores, fix and add a testcase.

Modified:
    llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp
    llvm/trunk/test/Transforms/DeadStoreElimination/simple.ll

Modified: llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp?rev=120363&r1=120362&r2=120363&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp Mon Nov 29 18:12:39 2010
@@ -222,7 +222,7 @@
     if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
       if (LoadInst *DepLoad = dyn_cast<LoadInst>(InstDep.getInst())) {
         if (SI->getPointerOperand() == DepLoad->getPointerOperand() &&
-            SI->getOperand(0) == DepLoad) {
+            SI->getOperand(0) == DepLoad && !SI->isVolatile()) {
           // DeleteDeadInstruction can delete the current instruction.  Save BBI
           // in case we need it.
           WeakVH NextInst(BBI);

Modified: llvm/trunk/test/Transforms/DeadStoreElimination/simple.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/DeadStoreElimination/simple.ll?rev=120363&r1=120362&r2=120363&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/DeadStoreElimination/simple.ll (original)
+++ llvm/trunk/test/Transforms/DeadStoreElimination/simple.ll Mon Nov 29 18:12:39 2010
@@ -34,3 +34,23 @@
   %tmp3 = load i32* @g, align 4
   ret i32 %tmp3
 }
+
+
+define void @test4(i32* %Q) {
+        %a = load i32* %Q
+        volatile store i32 %a, i32* %Q
+        ret void
+; CHECK: @test4
+; CHECK-NEXT: load i32
+; CHECK-NEXT: volatile store
+; CHECK-NEXT: ret void
+}
+
+define void @test5(i32* %Q) {
+        %a = volatile load i32* %Q
+        store i32 %a, i32* %Q
+        ret void
+; CHECK: @test5
+; CHECK-NEXT: volatile load
+; CHECK-NEXT: ret void
+}