[llvm] r212970 - Don't eliminate memcpy's when the address of the pointer may itself be relevant. Fixes PR18304. Patch by David Wiberg!
Nick Lewycky
nicholas at mxc.ca
Mon Jul 14 11:52:02 PDT 2014
Author: nicholas
Date: Mon Jul 14 13:52:02 2014
New Revision: 212970
URL: http://llvm.org/viewvc/llvm-project?rev=212970&view=rev
Log:
Don't eliminate memcpy's when the address of the pointer may itself be relevant. Fixes PR18304. Patch by David Wiberg!
Added:
llvm/trunk/test/Transforms/MemCpyOpt/capturing-func.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp
llvm/trunk/test/Transforms/MemCpyOpt/2008-02-24-MultipleUseofSRet.ll
llvm/trunk/test/Transforms/MemCpyOpt/2008-03-13-ReturnSlotBitcast.ll
llvm/trunk/test/Transforms/MemCpyOpt/loadstore-sret.ll
llvm/trunk/test/Transforms/MemCpyOpt/memcpy.ll
llvm/trunk/test/Transforms/MemCpyOpt/sret.ll
Modified: llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp?rev=212970&r1=212969&r2=212970&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp Mon Jul 14 13:52:02 2014
@@ -684,6 +684,12 @@ bool MemCpyOpt::performCallSlotOptzn(Ins
}
}
+ // Check that src isn't captured by the called function since the
+ // transformation can cause aliasing issues in that case.
+ for (unsigned i = 0, e = CS.arg_size(); i != e; ++i)
+ if (CS.getArgument(i) == cpySrc && !CS.doesNotCapture(i))
+ return false;
+
// Since we're changing the parameter to the callsite, we need to make sure
// that what would be the new parameter dominates the callsite.
DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
Modified: llvm/trunk/test/Transforms/MemCpyOpt/2008-02-24-MultipleUseofSRet.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/MemCpyOpt/2008-02-24-MultipleUseofSRet.ll?rev=212970&r1=212969&r2=212970&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/MemCpyOpt/2008-02-24-MultipleUseofSRet.ll (original)
+++ llvm/trunk/test/Transforms/MemCpyOpt/2008-02-24-MultipleUseofSRet.ll Mon Jul 14 13:52:02 2014
@@ -6,7 +6,7 @@ target triple = "i386-pc-linux-gnu"
%0 = type { x86_fp80, x86_fp80 }
-define internal fastcc void @initialize(%0* noalias sret %agg.result) nounwind {
+define internal fastcc void @initialize(%0* noalias nocapture sret %agg.result) nounwind {
entry:
%agg.result.03 = getelementptr %0* %agg.result, i32 0, i32 0
store x86_fp80 0xK00000000000000000000, x86_fp80* %agg.result.03
@@ -15,7 +15,7 @@ entry:
ret void
}
-declare fastcc x86_fp80 @passed_uninitialized(%0*) nounwind
+declare fastcc x86_fp80 @passed_uninitialized(%0* nocapture) nounwind
define fastcc void @badly_optimized() nounwind {
entry:
Modified: llvm/trunk/test/Transforms/MemCpyOpt/2008-03-13-ReturnSlotBitcast.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/MemCpyOpt/2008-03-13-ReturnSlotBitcast.ll?rev=212970&r1=212969&r2=212970&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/MemCpyOpt/2008-03-13-ReturnSlotBitcast.ll (original)
+++ llvm/trunk/test/Transforms/MemCpyOpt/2008-03-13-ReturnSlotBitcast.ll Mon Jul 14 13:52:02 2014
@@ -4,7 +4,7 @@ target datalayout = "E-p:64:64:64-i1:8:8
%a = type { i32 }
%b = type { float }
-declare void @g(%a*)
+declare void @g(%a* nocapture)
define float @f() {
entry:
Added: llvm/trunk/test/Transforms/MemCpyOpt/capturing-func.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/MemCpyOpt/capturing-func.ll?rev=212970&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/MemCpyOpt/capturing-func.ll (added)
+++ llvm/trunk/test/Transforms/MemCpyOpt/capturing-func.ll Mon Jul 14 13:52:02 2014
@@ -0,0 +1,22 @@
+; RUN: opt < %s -basicaa -memcpyopt -S | FileCheck %s
+
+target datalayout = "e"
+
+declare void @foo(i8*)
+declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32, i1) nounwind
+
+define void @test() {
+ %ptr1 = alloca i8
+ %ptr2 = alloca i8
+ call void @foo(i8* %ptr2)
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %ptr1, i8* %ptr2, i32 1, i32 1, i1 false)
+ call void @foo(i8* %ptr1)
+ ret void
+
+ ; Check that the transformation isn't applied if the called function can
+ ; capture the pointer argument (i.e. the nocapture attribute isn't present)
+ ; CHECK-LABEL: @test(
+ ; CHECK: call void @foo(i8* %ptr2)
+ ; CHECK-NEXT: call void @llvm.memcpy
+ ; CHECK-NEXT: call void @foo(i8* %ptr1)
+}
Modified: llvm/trunk/test/Transforms/MemCpyOpt/loadstore-sret.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/MemCpyOpt/loadstore-sret.ll?rev=212970&r1=212969&r2=212970&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/MemCpyOpt/loadstore-sret.ll (original)
+++ llvm/trunk/test/Transforms/MemCpyOpt/loadstore-sret.ll Mon Jul 14 13:52:02 2014
@@ -22,4 +22,4 @@ _ZNSt8auto_ptrIiED1Ev.exit:
ret void
}
-declare void @_Z3barv(%"class.std::auto_ptr"* sret)
+declare void @_Z3barv(%"class.std::auto_ptr"* nocapture sret)
Modified: llvm/trunk/test/Transforms/MemCpyOpt/memcpy.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/MemCpyOpt/memcpy.ll?rev=212970&r1=212969&r2=212970&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/MemCpyOpt/memcpy.ll (original)
+++ llvm/trunk/test/Transforms/MemCpyOpt/memcpy.ll Mon Jul 14 13:52:02 2014
@@ -29,7 +29,7 @@ entry:
; CHECK: ret void
}
-declare void @ccoshl(%0* sret , x86_fp80, x86_fp80) nounwind
+declare void @ccoshl(%0* nocapture sret, x86_fp80, x86_fp80) nounwind
; The intermediate alloca and one of the memcpy's should be eliminated, the
@@ -202,7 +202,7 @@ define void @test10(%opaque* noalias noc
ret void
}
-declare void @f1(%struct.big* sret)
+declare void @f1(%struct.big* nocapture sret)
declare void @f2(%struct.big*)
; CHECK: attributes [[NUW]] = { nounwind }
Modified: llvm/trunk/test/Transforms/MemCpyOpt/sret.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/MemCpyOpt/sret.ll?rev=212970&r1=212969&r2=212970&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/MemCpyOpt/sret.ll (original)
+++ llvm/trunk/test/Transforms/MemCpyOpt/sret.ll Mon Jul 14 13:52:02 2014
@@ -25,6 +25,6 @@ entry:
ret void
}
-declare void @ccoshl(%0* noalias sret, %0* byval) nounwind
+declare void @ccoshl(%0* noalias nocapture sret, %0* byval) nounwind
declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32, i1) nounwind
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