[llvm] r328748 - [MemorySSA] Consider callsite args for hashing and equality.

Tom Stellard via llvm-commits llvm-commits at lists.llvm.org
Mon Apr 9 19:42:35 PDT 2018


On 04/09/2018 07:13 PM, George Burgess IV wrote:
> Thanks, Hal!
> 
> Is this OK with you, too, Tom?
> 

Yes, I've merged this: r329663.

-Tom

> George
> 
> On Fri, Mar 30, 2018 at 1:33 PM, Hal Finkel <hfinkel at anl.gov <mailto:hfinkel at anl.gov>> wrote:
> 
> 
>     On 03/30/2018 03:04 PM, George Burgess IV wrote:
>>     Hello Tom and Hal,
>>
>>     I would like approval to pick this (and its follow-up, which I'll ping you both about in a sec :) ) into the 6.0 release branch. It fixes a misoptimization that dates back to 5.0, but since 5.0.2rc2 was just cut, I think it's best to leave that as-is.
> 
>     I agree. Pulling this (along with r328755) into the release branch is appropriate.
> 
>      -Hal
> 
> 
>>
>>     Thanks,
>>     George
>>
>>     On Wed, Mar 28, 2018 at 5:54 PM, George Burgess IV via llvm-commits <llvm-commits at lists.llvm.org <mailto:llvm-commits at lists.llvm.org>> wrote:
>>
>>         Author: gbiv
>>         Date: Wed Mar 28 17:54:39 2018
>>         New Revision: 328748
>>
>>         URL: http://llvm.org/viewvc/llvm-project?rev=328748&view=rev <http://llvm.org/viewvc/llvm-project?rev=328748&view=rev>
>>         Log:
>>         [MemorySSA] Consider callsite args for hashing and equality.
>>
>>         We use a `DenseMap<MemoryLocOrCall, MemlocStackInfo>` to keep track of
>>         prior work when optimizing uses in MemorySSA. Because we weren't
>>         accounting for callsite arguments in either the hash code or equality
>>         tests for `MemoryLocOrCall`s, we optimized uses too aggressively in
>>         some rare cases.
>>
>>         Fix by Daniel Berlin.
>>
>>         Should fix PR36883.
>>
>>         Added:
>>             llvm/trunk/test/Analysis/MemorySSA/pr36883.ll
>>         Modified:
>>             llvm/trunk/lib/Analysis/MemorySSA.cpp
>>
>>         Modified: llvm/trunk/lib/Analysis/MemorySSA.cpp
>>         URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MemorySSA.cpp?rev=328748&r1=328747&r2=328748&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MemorySSA.cpp?rev=328748&r1=328747&r2=328748&view=diff>
>>         ==============================================================================
>>         --- llvm/trunk/lib/Analysis/MemorySSA.cpp (original)
>>         +++ llvm/trunk/lib/Analysis/MemorySSA.cpp Wed Mar 28 17:54:39 2018
>>         @@ -153,9 +153,14 @@ public:
>>              if (IsCall != Other.IsCall)
>>                return false;
>>
>>         -    if (IsCall)
>>         -      return CS.getCalledValue() == Other.CS.getCalledValue();
>>         -    return Loc == Other.Loc;
>>         +    if (!IsCall)
>>         +      return Loc == Other.Loc;
>>         +
>>         +    if (CS.getCalledValue() != Other.CS.getCalledValue())
>>         +      return false;
>>         +
>>         +    assert(CS.arg_size() == Other.CS.arg_size());
>>         +    return std::equal(CS.arg_begin(), CS.arg_end(), Other.CS.arg_begin());
>>            }
>>
>>          private:
>>         @@ -179,12 +184,18 @@ template <> struct DenseMapInfo<MemoryLo
>>            }
>>
>>            static unsigned getHashValue(const MemoryLocOrCall &MLOC) {
>>         -    if (MLOC.IsCall)
>>         -      return hash_combine(MLOC.IsCall,
>>         -                          DenseMapInfo<const Value *>::getHashValue(
>>         -                              MLOC.getCS().getCalledValue()));
>>         -    return hash_combine(
>>         -        MLOC.IsCall, DenseMapInfo<MemoryLocation>::getHashValue(MLOC.getLoc()));
>>         +    if (!MLOC.IsCall)
>>         +      return hash_combine(
>>         +          MLOC.IsCall,
>>         +          DenseMapInfo<MemoryLocation>::getHashValue(MLOC.getLoc()));
>>         +
>>         +    hash_code hash =
>>         +        hash_combine(MLOC.IsCall, DenseMapInfo<const Value *>::getHashValue(
>>         +                                      MLOC.getCS().getCalledValue()));
>>         +
>>         +    for (const Value *Arg : MLOC.getCS().args())
>>         +      hash = hash_combine(hash, DenseMapInfo<const Value *>::getHashValue(Arg));
>>         +    return hash;
>>            }
>>
>>            static bool isEqual(const MemoryLocOrCall &LHS, const MemoryLocOrCall &RHS) {
>>
>>         Added: llvm/trunk/test/Analysis/MemorySSA/pr36883.ll
>>         URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/MemorySSA/pr36883.ll?rev=328748&view=auto <http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/MemorySSA/pr36883.ll?rev=328748&view=auto>
>>         ==============================================================================
>>         --- llvm/trunk/test/Analysis/MemorySSA/pr36883.ll (added)
>>         +++ llvm/trunk/test/Analysis/MemorySSA/pr36883.ll Wed Mar 28 17:54:39 2018
>>         @@ -0,0 +1,38 @@
>>         +; RUN: opt -basicaa -memoryssa -analyze < %s 2>&1 -S | FileCheck %s
>>         +; RUN: opt -aa-pipeline=basic-aa -passes='print<memoryssa>,verify<memoryssa>' -S < %s 2>&1 | FileCheck %s
>>         +;
>>         +; We weren't properly considering the args in callsites in equality or hashing.
>>         +
>>         +target triple = "armv7-dcg-linux-gnueabi"
>>         +
>>         +; CHECK-LABEL: define <8 x i16> @vpx_idct32_32_neon
>>         +define <8 x i16> @vpx_idct32_32_neon(i8* %p, <8 x i16> %v) {
>>         +entry:
>>         +; CHECK: MemoryUse(liveOnEntry)
>>         +  %load1 = call <8 x i16> @llvm.arm.neon.vld1.v8i16.p0i8(i8* %p, i32 2) #4 ; load CSE replacement
>>         +
>>         +; CHECK: 1 = MemoryDef(liveOnEntry)
>>         +  call void @llvm.arm.neon.vst1.p0i8.v8i16(i8* %p, <8 x i16> %v, i32 2) #4 ; clobber
>>         +
>>         +  %p_next = getelementptr inbounds i8, i8* %p, i32 16
>>         +; CHECK: MemoryUse(liveOnEntry)
>>         +  %load2 = call <8 x i16> @llvm.arm.neon.vld1.v8i16.p0i8(i8* %p_next, i32 2) #4 ; non-aliasing load needed to trigger bug
>>         +
>>         +; CHECK: MemoryUse(1)
>>         +  %load3 = call <8 x i16> @llvm.arm.neon.vld1.v8i16.p0i8(i8* %p, i32 2) #4 ; load CSE removed
>>         +
>>         +  %add = add <8 x i16> %load1, %load2
>>         +  %ret = add <8 x i16> %add, %load3
>>         +  ret <8 x i16> %ret
>>         +}
>>         +
>>         +; Function Attrs: argmemonly nounwind readonly
>>         +declare <8 x i16> @llvm.arm.neon.vld1.v8i16.p0i8(i8*, i32) #2
>>         +
>>         +; Function Attrs: argmemonly nounwind
>>         +declare void @llvm.arm.neon.vst1.p0i8.v8i16(i8*, <8 x i16>, i32) #1
>>         +
>>         +attributes #1 = { argmemonly nounwind }
>>         +attributes #2 = { argmemonly nounwind readonly }
>>         +attributes #3 = { nounwind readnone }
>>         +attributes #4 = { nounwind }
>>
>>
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>>
>>
> 
>     -- 
>     Hal Finkel
>     Lead, Compiler Technology and Programming Languages
>     Leadership Computing Facility
>     Argonne National Laboratory
> 
> 



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