[llvm-commits] [llvm] r142150 - in /llvm/trunk: lib/Transforms/Scalar/MemCpyOptimizer.cpp test/Transforms/MemCpyOpt/memcpy.ll
Nick Lewycky
nicholas at mxc.ca
Sun Oct 16 13:13:32 PDT 2011
Author: nicholas
Date: Sun Oct 16 15:13:32 2011
New Revision: 142150
URL: http://llvm.org/viewvc/llvm-project?rev=142150&view=rev
Log:
When looking for dependencies on the src pointer, scan the src pointer. Scanning
on the memcpy call will pull up other unrelated stuff. Fixes PR11142.
Modified:
llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp
llvm/trunk/test/Transforms/MemCpyOpt/memcpy.ll
Modified: llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp?rev=142150&r1=142149&r2=142150&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp Sun Oct 16 15:13:32 2011
@@ -806,21 +806,26 @@
// a) memcpy-memcpy xform which exposes redundance for DSE.
// b) call-memcpy xform for return slot optimization.
MemDepResult DepInfo = MD->getDependency(M);
- if (!DepInfo.isClobber())
- return false;
-
- if (MemCpyInst *MDep = dyn_cast<MemCpyInst>(DepInfo.getInst()))
- return processMemCpyMemCpyDependence(M, MDep, CopySize->getZExtValue());
-
- if (CallInst *C = dyn_cast<CallInst>(DepInfo.getInst())) {
- if (performCallSlotOptzn(M, M->getDest(), M->getSource(),
- CopySize->getZExtValue(), C)) {
- MD->removeInstruction(M);
- M->eraseFromParent();
- return true;
+ if (DepInfo.isClobber()) {
+ if (CallInst *C = dyn_cast<CallInst>(DepInfo.getInst())) {
+ if (performCallSlotOptzn(M, M->getDest(), M->getSource(),
+ CopySize->getZExtValue(), C)) {
+ MD->removeInstruction(M);
+ M->eraseFromParent();
+ return true;
+ }
}
}
+ AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
+ AliasAnalysis::Location SrcLoc = AA.getLocationForSource(M);
+ MemDepResult SrcDepInfo = MD->getPointerDependencyFrom(SrcLoc, true,
+ M, M->getParent());
+ if (SrcDepInfo.isClobber()) {
+ if (MemCpyInst *MDep = dyn_cast<MemCpyInst>(SrcDepInfo.getInst()))
+ return processMemCpyMemCpyDependence(M, MDep, CopySize->getZExtValue());
+ }
+
return false;
}
Modified: llvm/trunk/test/Transforms/MemCpyOpt/memcpy.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/MemCpyOpt/memcpy.ll?rev=142150&r1=142149&r2=142150&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/MemCpyOpt/memcpy.ll (original)
+++ llvm/trunk/test/Transforms/MemCpyOpt/memcpy.ll Sun Oct 16 15:13:32 2011
@@ -59,7 +59,7 @@
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %agg.result2, i8* %x.01, i32 32, i32 16, i1 false)
ret void
; CHECK: @test3
-; CHECK-NEXT: %agg.result2 = bitcast
+; CHECK-NEXT: %agg.result1 = bitcast
; CHECK-NEXT: call void @llvm.memcpy
; CHECK-NEXT: ret void
}
@@ -130,3 +130,21 @@
declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32, i1) nounwind
+; PR11142 - When looking for a memcpy-memcpy dependency, don't get stuck on
+; instructions between the memcpy's that only affect the destination pointer.
+ at test8.str = internal constant [7 x i8] c"ABCDEF\00"
+
+define void @test8() {
+; CHECK: test8
+ %A = tail call i8* @malloc(i32 10)
+ %B = getelementptr inbounds i8* %A, i64 2
+ tail call void @llvm.memcpy.p0i8.p0i8.i32(i8* %B, i8* getelementptr inbounds ([7 x i8]* @test8.str, i64 0, i64 0), i32 7, i32 1, i1 false)
+; CHECK: tail call void @llvm.memcpy.p0i8.p0i8.i32(i8* %D, i8* getelementptr
+ %C = tail call i8* @malloc(i32 10)
+ %D = getelementptr inbounds i8* %C, i64 2
+ tail call void @llvm.memcpy.p0i8.p0i8.i32(i8* %D, i8* %B, i32 7, i32 1, i1 false)
+; CHECK: tail call void @llvm.memcpy.p0i8.p0i8.i32(i8* %D, i8* getelementptr
+ ret void
+}
+
+declare noalias i8* @malloc(i32)
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