[llvm] r221168 - Normally an 'optnone' function goes through fast-isel, which does not

Adrian Prantl aprantl at apple.com
Mon Nov 3 15:55:13 PST 2014


Sorry for the noise! I relayed the bot’s message without actually closely reading it. The bot also recovered since.
Looking at the error message it actually appears as if the tests were kill -9’ed. That does not make a lot of sense. We’re still investigating why this happened. 

-- adrian

> On Nov 3, 2014, at 3:50 PM, Robinson, Paul <Paul_Robinson at playstation.sony.com> wrote:
> 
> Hi Adrian,
> It's a little hard to envision how an LLVM change to disable an optimization
> for functions with the 'optnone' attribute could possibly cause Clang driver 
> test failures.  I can't repro this with r221169 on Linux.
> --paulr
> 
>> -----Original Message-----
>> From: Adrian Prantl [mailto:aprantl at apple.com]
>> Sent: Monday, November 03, 2014 11:42 AM
>> To: Robinson, Paul
>> Cc: llvm-commits at cs.uiuc.edu
>> Subject: Re: [llvm] r221168 - Normally an 'optnone' function goes through
>> fast-isel, which does not
>> 
>> Actually, this link is much more useful:
>> 
>> http://lab.llvm.org:8080/green/job/clang-stage1-configure-
>> RA_check/757/consoleFull#-7971533768254eaf0-7326-4999-85b0-388101f2d404
>> 
>> 
>>> On Nov 3, 2014, at 11:40 AM, Adrian Prantl <aprantl at apple.com> wrote:
>>> 
>>> I don’t think our new bots send out emails yet, so here goes:
>>> 
>>> Project Clang Stage 1: configure, RA, using system compiler build
>> r221169 (#443): UNSTABLE in 18 min:
>> http://lab.llvm.org:8080/green/job/clang-stage1-configure-RA/443/ -
>> blamelist: rnk, probinson, Duncan P. N. Exon Smith
>>> 
>>> -- adrian
>>> 
>>> 
>>>> On Nov 3, 2014, at 10:19 AM, Paul Robinson
>> <paul_robinson at playstation.sony.com> wrote:
>>>> 
>>>> Author: probinson
>>>> Date: Mon Nov  3 12:19:26 2014
>>>> New Revision: 221168
>>>> 
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=221168&view=rev
>>>> Log:
>>>> Normally an 'optnone' function goes through fast-isel, which does not
>>>> call DAGCombiner. But we ran into a case (on Windows) where the
>>>> calling convention causes argument lowering to bail out of fast-isel,
>>>> and we end up in CodeGenAndEmitDAG() which does run DAGCombiner.
>>>> So, we need to make DAGCombiner check for 'optnone' after all.
>>>> 
>>>> Commit includes the test that found this, plus another one that got
>>>> missed in the original optnone work.
>>>> 
>>>> Added:
>>>>  llvm/trunk/test/CodeGen/X86/fastmath-optnone.ll
>>>>  llvm/trunk/test/Transforms/FunctionAttrs/optnone-simple.ll
>>>> Modified:
>>>>  llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
>>>> 
>>>> Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
>>>> URL: http://llvm.org/viewvc/llvm-
>> project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=221168&r1=
>> 221167&r2=221168&view=diff
>>>> 
>> ==========================================================================
>> ====
>>>> --- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
>>>> +++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Mon Nov  3
>> 12:19:26 2014
>>>> @@ -1155,6 +1155,13 @@ void DAGCombiner::Run(CombineLevel AtLev
>>>> LegalOperations = Level >= AfterLegalizeVectorOps;
>>>> LegalTypes = Level >= AfterLegalizeTypes;
>>>> 
>>>> +  // Early exit if this basic block is in an optnone function.
>>>> +  AttributeSet FnAttrs =
>>>> +    DAG.getMachineFunction().getFunction()->getAttributes();
>>>> +  if (FnAttrs.hasAttribute(AttributeSet::FunctionIndex,
>>>> +                           Attribute::OptimizeNone))
>>>> +    return;
>>>> +
>>>> // Add all the dag nodes to the worklist.
>>>> for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
>>>>      E = DAG.allnodes_end(); I != E; ++I)
>>>> 
>>>> Added: llvm/trunk/test/CodeGen/X86/fastmath-optnone.ll
>>>> URL: http://llvm.org/viewvc/llvm-
>> project/llvm/trunk/test/CodeGen/X86/fastmath-
>> optnone.ll?rev=221168&view=auto
>>>> 
>> ==========================================================================
>> ====
>>>> --- llvm/trunk/test/CodeGen/X86/fastmath-optnone.ll (added)
>>>> +++ llvm/trunk/test/CodeGen/X86/fastmath-optnone.ll Mon Nov  3 12:19:26
>> 2014
>>>> @@ -0,0 +1,35 @@
>>>> +; RUN: llc < %s -mcpu=corei7 -march=x86-64 -mattr=+sse2 | FileCheck %s
>>>> +; Verify that floating-point operations inside 'optnone' functions
>>>> +; are not optimized even if unsafe-fp-math is set.
>>>> +
>>>> +define float @foo(float %x) #0 {
>>>> +entry:
>>>> +  %add = fadd fast float %x, %x
>>>> +  %add1 = fadd fast float %add, %x
>>>> +  ret float %add1
>>>> +}
>>>> +
>>>> +; CHECK-LABEL: @foo
>>>> +; CHECK-NOT: add
>>>> +; CHECK: mul
>>>> +; CHECK-NOT: add
>>>> +; CHECK: ret
>>>> +
>>>> +define float @fooWithOptnone(float %x) #1 {
>>>> +entry:
>>>> +  %add = fadd fast float %x, %x
>>>> +  %add1 = fadd fast float %add, %x
>>>> +  ret float %add1
>>>> +}
>>>> +
>>>> +; CHECK-LABEL: @fooWithOptnone
>>>> +; CHECK-NOT: mul
>>>> +; CHECK: add
>>>> +; CHECK-NOT: mul
>>>> +; CHECK: add
>>>> +; CHECK-NOT: mul
>>>> +; CHECK: ret
>>>> +
>>>> +
>>>> +attributes #0 = { "unsafe-fp-math"="true" }
>>>> +attributes #1 = { noinline optnone "unsafe-fp-math"="true" }
>>>> 
>>>> Added: llvm/trunk/test/Transforms/FunctionAttrs/optnone-simple.ll
>>>> URL: http://llvm.org/viewvc/llvm-
>> project/llvm/trunk/test/Transforms/FunctionAttrs/optnone-
>> simple.ll?rev=221168&view=auto
>>>> 
>> ==========================================================================
>> ====
>>>> --- llvm/trunk/test/Transforms/FunctionAttrs/optnone-simple.ll (added)
>>>> +++ llvm/trunk/test/Transforms/FunctionAttrs/optnone-simple.ll Mon Nov
>> 3 12:19:26 2014
>>>> @@ -0,0 +1,135 @@
>>>> +; RUN: opt -O3 -S < %s | FileCheck %s
>>>> +; Show 'optnone' suppresses optimizations.
>>>> +
>>>> +; Two attribute groups that differ only by 'optnone'.
>>>> +; 'optnone' requires 'noinline' so #0 is 'noinline' by itself,
>>>> +; even though it would otherwise be irrelevant to this example.
>>>> +attributes #0 = { noinline }
>>>> +attributes #1 = { noinline optnone }
>>>> +
>>>> +; int iadd(int a, int b){ return a + b; }
>>>> +
>>>> +define i32 @iadd_optimize(i32 %a, i32 %b) #0 {
>>>> +entry:
>>>> +  %a.addr = alloca i32, align 4
>>>> +  %b.addr = alloca i32, align 4
>>>> +  store i32 %a, i32* %a.addr, align 4
>>>> +  store i32 %b, i32* %b.addr, align 4
>>>> +  %0 = load i32* %a.addr, align 4
>>>> +  %1 = load i32* %b.addr, align 4
>>>> +  %add = add nsw i32 %0, %1
>>>> +  ret i32 %add
>>>> +}
>>>> +
>>>> +; CHECK-LABEL: @iadd_optimize
>>>> +; CHECK-NOT: alloca
>>>> +; CHECK-NOT: store
>>>> +; CHECK-NOT: load
>>>> +; CHECK: ret
>>>> +
>>>> +define i32 @iadd_optnone(i32 %a, i32 %b) #1 {
>>>> +entry:
>>>> +  %a.addr = alloca i32, align 4
>>>> +  %b.addr = alloca i32, align 4
>>>> +  store i32 %a, i32* %a.addr, align 4
>>>> +  store i32 %b, i32* %b.addr, align 4
>>>> +  %0 = load i32* %a.addr, align 4
>>>> +  %1 = load i32* %b.addr, align 4
>>>> +  %add = add nsw i32 %0, %1
>>>> +  ret i32 %add
>>>> +}
>>>> +
>>>> +; CHECK-LABEL: @iadd_optnone
>>>> +; CHECK: alloca i32
>>>> +; CHECK: alloca i32
>>>> +; CHECK: store i32
>>>> +; CHECK: store i32
>>>> +; CHECK: load i32
>>>> +; CHECK: load i32
>>>> +; CHECK: add nsw i32
>>>> +; CHECK: ret i32
>>>> +
>>>> +; float fsub(float a, float b){ return a - b; }
>>>> +
>>>> +define float @fsub_optimize(float %a, float %b) #0 {
>>>> +entry:
>>>> +  %a.addr = alloca float, align 4
>>>> +  %b.addr = alloca float, align 4
>>>> +  store float %a, float* %a.addr, align 4
>>>> +  store float %b, float* %b.addr, align 4
>>>> +  %0 = load float* %a.addr, align 4
>>>> +  %1 = load float* %b.addr, align 4
>>>> +  %sub = fsub float %0, %1
>>>> +  ret float %sub
>>>> +}
>>>> +
>>>> +; CHECK-LABEL: @fsub_optimize
>>>> +; CHECK-NOT: alloca
>>>> +; CHECK-NOT: store
>>>> +; CHECK-NOT: load
>>>> +; CHECK: ret
>>>> +
>>>> +define float @fsub_optnone(float %a, float %b) #1 {
>>>> +entry:
>>>> +  %a.addr = alloca float, align 4
>>>> +  %b.addr = alloca float, align 4
>>>> +  store float %a, float* %a.addr, align 4
>>>> +  store float %b, float* %b.addr, align 4
>>>> +  %0 = load float* %a.addr, align 4
>>>> +  %1 = load float* %b.addr, align 4
>>>> +  %sub = fsub float %0, %1
>>>> +  ret float %sub
>>>> +}
>>>> +
>>>> +; CHECK-LABEL: @fsub_optnone
>>>> +; CHECK: alloca float
>>>> +; CHECK: alloca float
>>>> +; CHECK: store float
>>>> +; CHECK: store float
>>>> +; CHECK: load float
>>>> +; CHECK: load float
>>>> +; CHECK: fsub float
>>>> +; CHECK: ret float
>>>> +
>>>> +; typedef float __attribute__((ext_vector_type(4))) float4;
>>>> +; float4 vmul(float4 a, float4 b){ return a * b; }
>>>> +
>>>> +define <4 x float> @vmul_optimize(<4 x float> %a, <4 x float> %b) #0 {
>>>> +entry:
>>>> +  %a.addr = alloca <4 x float>, align 16
>>>> +  %b.addr = alloca <4 x float>, align 16
>>>> +  store <4 x float> %a, <4 x float>* %a.addr, align 16
>>>> +  store <4 x float> %b, <4 x float>* %b.addr, align 16
>>>> +  %0 = load <4 x float>* %a.addr, align 16
>>>> +  %1 = load <4 x float>* %b.addr, align 16
>>>> +  %mul = fmul <4 x float> %0, %1
>>>> +  ret <4 x float> %mul
>>>> +}
>>>> +
>>>> +; CHECK-LABEL: @vmul_optimize
>>>> +; CHECK-NOT: alloca
>>>> +; CHECK-NOT: store
>>>> +; CHECK-NOT: load
>>>> +; CHECK: ret
>>>> +
>>>> +define <4 x float> @vmul_optnone(<4 x float> %a, <4 x float> %b) #1 {
>>>> +entry:
>>>> +  %a.addr = alloca <4 x float>, align 16
>>>> +  %b.addr = alloca <4 x float>, align 16
>>>> +  store <4 x float> %a, <4 x float>* %a.addr, align 16
>>>> +  store <4 x float> %b, <4 x float>* %b.addr, align 16
>>>> +  %0 = load <4 x float>* %a.addr, align 16
>>>> +  %1 = load <4 x float>* %b.addr, align 16
>>>> +  %mul = fmul <4 x float> %0, %1
>>>> +  ret <4 x float> %mul
>>>> +}
>>>> +
>>>> +; CHECK-LABEL: @vmul_optnone
>>>> +; CHECK: alloca <4 x float>
>>>> +; CHECK: alloca <4 x float>
>>>> +; CHECK: store <4 x float>
>>>> +; CHECK: store <4 x float>
>>>> +; CHECK: load <4 x float>
>>>> +; CHECK: load <4 x float>
>>>> +; CHECK: fmul <4 x float>
>>>> +; CHECK: ret
>>>> 
>>>> 
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