[llvm-commits] [llvm] r171279 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp test/Transforms/InstCombine/store.ll

[Chris Lattner]

Author: lattner
Date: Mon Dec 31 02:10:58 2012
New Revision: 171279

URL: http://llvm.org/viewvc/llvm-project?rev=171279&view=rev
Log:
teach instcombine to preserve TBAA tag when merging two stores, part of
PR14753

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
    llvm/trunk/test/Transforms/InstCombine/store.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp?rev=171279&r1=171278&r2=171279&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp Mon Dec 31 02:10:58 2012
@@ -802,6 +802,13 @@
   InsertNewInstBefore(NewSI, *BBI);
   NewSI->setDebugLoc(OtherStore->getDebugLoc()); 
 
+  // If the two stores had the same TBAA tag, preserve it.
+  if (MDNode *TBAATag1 = SI.getMetadata(LLVMContext::MD_tbaa))
+    if (MDNode *TBAATag2 = OtherStore->getMetadata(LLVMContext::MD_tbaa))
+      if (TBAATag1 == TBAATag2)
+        NewSI->setMetadata(LLVMContext::MD_tbaa, TBAATag1);
+
+  
   // Nuke the old stores.
   EraseInstFromFunction(SI);
   EraseInstFromFunction(*OtherStore);

Modified: llvm/trunk/test/Transforms/InstCombine/store.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/store.ll?rev=171279&r1=171278&r2=171279&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/store.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/store.ll Mon Dec 31 02:10:58 2012
@@ -83,3 +83,37 @@
 ; CHECK-NEXT:  ret void
 }
 
+
+; PR14753 - merging two stores should preserve the TBAA tag.
+define void @test6(i32 %n, float* %a, i32* %gi) nounwind uwtable ssp {
+entry:
+  store i32 42, i32* %gi, align 4, !tbaa !0
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.body, %entry
+  %storemerge = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  %0 = load i32* %gi, align 4, !tbaa !0
+  %cmp = icmp slt i32 %0, %n
+  br i1 %cmp, label %for.body, label %for.end
+
+for.body:                                         ; preds = %for.cond
+  %idxprom = sext i32 %0 to i64
+  %arrayidx = getelementptr inbounds float* %a, i64 %idxprom
+  store float 0.000000e+00, float* %arrayidx, align 4, !tbaa !3
+  %1 = load i32* %gi, align 4, !tbaa !0
+  %inc = add nsw i32 %1, 1
+  store i32 %inc, i32* %gi, align 4, !tbaa !0
+  br label %for.cond
+
+for.end:                                          ; preds = %for.cond
+  ret void
+; CHECK: @test6
+; CHECK: for.cond:
+; CHECK-NEXT: phi i32 [ 42
+; CHECK-NEXT: store i32 %storemerge, i32* %gi, align 4, !tbaa !0
+}
+
+!0 = metadata !{metadata !"int", metadata !1}
+!1 = metadata !{metadata !"omnipotent char", metadata !2}
+!2 = metadata !{metadata !"Simple C/C++ TBAA"}
+!3 = metadata !{metadata !"float", metadata !1}