[llvm-commits] [llvm] r144863 - in /llvm/trunk: lib/CodeGen/SelectionDAG/DAGCombiner.cpp test/CodeGen/X86/vec_extract-sse4.ll

Eli Friedman eli.friedman at gmail.com
Wed Nov 16 15:50:23 PST 2011


Author: efriedma
Date: Wed Nov 16 17:50:22 2011
New Revision: 144863

URL: http://llvm.org/viewvc/llvm-project?rev=144863&view=rev
Log:
Make sure to replace the chain properly when DAGCombining a LOAD+EXTRACT_VECTOR_ELT into a single LOAD.  Fixes PR10747/PR11393.


Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
    llvm/trunk/test/CodeGen/X86/vec_extract-sse4.ll

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=144863&r1=144862&r2=144863&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Wed Nov 16 17:50:22 2011
@@ -6936,10 +6936,23 @@
                            DAG.getConstant(PtrOff, PtrType));
     }
 
-    return DAG.getLoad(LVT, N->getDebugLoc(), LN0->getChain(), NewPtr,
-                       LN0->getPointerInfo().getWithOffset(PtrOff),
-                       LN0->isVolatile(), LN0->isNonTemporal(), 
-                       LN0->isInvariant(), Align);
+    // The replacement we need to do here is a little tricky: we need to
+    // replace an extractelement of a load with a load.
+    // Use ReplaceAllUsesOfValuesWith to do the replacement.
+    SDValue Load = DAG.getLoad(LVT, N->getDebugLoc(), LN0->getChain(), NewPtr,
+                               LN0->getPointerInfo().getWithOffset(PtrOff),
+                               LN0->isVolatile(), LN0->isNonTemporal(), 
+                               LN0->isInvariant(), Align);
+    WorkListRemover DeadNodes(*this);
+    SDValue From[] = { SDValue(N, 0), SDValue(LN0,1) };
+    SDValue To[] = { Load.getValue(0), Load.getValue(1) };
+    DAG.ReplaceAllUsesOfValuesWith(From, To, 2, &DeadNodes);
+    // Since we're explcitly calling ReplaceAllUses, add the new node to the
+    // worklist explicitly as well.
+    AddToWorkList(Load.getNode());
+    // Make sure to revisit this node to clean it up; it will usually be dead.
+    AddToWorkList(N);
+    return SDValue(N, 0);
   }
 
   return SDValue();

Modified: llvm/trunk/test/CodeGen/X86/vec_extract-sse4.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/vec_extract-sse4.ll?rev=144863&r1=144862&r2=144863&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/vec_extract-sse4.ll (original)
+++ llvm/trunk/test/CodeGen/X86/vec_extract-sse4.ll Wed Nov 16 17:50:22 2011
@@ -2,7 +2,7 @@
 ; RUN: not grep extractps   %t
 ; RUN: not grep pextrd      %t
 ; RUN: not grep pshufd  %t
-; RUN: grep movss   %t | count 2
+; RUN: not grep movss   %t
 
 define void @t1(float* %R, <4 x float>* %P1) nounwind {
 	%X = load <4 x float>* %P1





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