[llvm] 6ef4505 - [funcattrs] Infer nosync from readnone and non-convergent

Philip Reames via llvm-commits llvm-commits at lists.llvm.org
Thu Apr 1 12:17:45 PDT 2021


Fixed in a8ac881.

On 4/1/21 12:01 PM, Philip Reames via llvm-commits wrote:
> This appears to have broken a bunch of bots.  I missed updating some 
> target specific tests.
>
> I'll have that fixed shortly.
>
> Philip
>
> On 4/1/21 11:37 AM, Philip Reames via llvm-commits wrote:
>> Author: Philip Reames
>> Date: 2021-04-01T11:37:34-07:00
>> New Revision: 6ef4505298be08b8cb4243c7d28751e0e315370a
>>
>> URL: 
>> https://github.com/llvm/llvm-project/commit/6ef4505298be08b8cb4243c7d28751e0e315370a
>> DIFF: 
>> https://github.com/llvm/llvm-project/commit/6ef4505298be08b8cb4243c7d28751e0e315370a.diff
>>
>> LOG: [funcattrs] Infer nosync from readnone and non-convergent
>>
>> This implements the most basic possible nosync inference. The choice 
>> of inference rule is taken from the comments in attributor and the 
>> discussion on the review of the change which introduced the nosync 
>> attribute (0626367202c).
>>
>> This is deliberately minimal. As noted in code comments, I do plan to 
>> add a more robust inference which actually scans the function IR 
>> directly, but a) I need to do some refactoring of the attributor code 
>> to use common interfaces, and b) I wanted to get something in. I also 
>> wanted to minimize the "interesting" analysis discussion since that's 
>> time intensive.
>>
>> Context: This combines with existing nofree attribute inference to 
>> help prove dereferenceability in the ongoing deref-at-point semantics 
>> work.
>>
>> Differential Revision: https://reviews.llvm.org/D99749
>>
>> Added:
>>
>> Modified:
>>      llvm/lib/Transforms/IPO/FunctionAttrs.cpp
>>      llvm/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll
>>      llvm/test/Other/cgscc-devirt-iteration.ll
>>      llvm/test/Other/cgscc-iterate-function-mutation.ll
>>      llvm/test/Other/cgscc-observe-devirt.ll
>>      llvm/test/Transforms/FunctionAttrs/atomic.ll
>>      llvm/test/Transforms/FunctionAttrs/incompatible_fn_attrs.ll
>>      llvm/test/Transforms/FunctionAttrs/nofree-attributor.ll
>>      llvm/test/Transforms/FunctionAttrs/norecurse.ll
>>      llvm/test/Transforms/FunctionAttrs/nosync.ll
>>      llvm/test/Transforms/FunctionAttrs/nounwind.ll
>>      llvm/test/Transforms/FunctionAttrs/optnone.ll
>>      llvm/test/Transforms/Inline/cgscc-update.ll
>>
>> Removed:
>>
>>
>> ################################################################################ 
>>
>> diff  --git a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp 
>> b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
>> index 6730824e860ac..87eaf2dd2fdf4 100644
>> --- a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
>> +++ b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
>> @@ -79,6 +79,7 @@ STATISTIC(NumNoRecurse, "Number of functions marked 
>> as norecurse");
>>   STATISTIC(NumNoUnwind, "Number of functions marked as nounwind");
>>   STATISTIC(NumNoFree, "Number of functions marked as nofree");
>>   STATISTIC(NumWillReturn, "Number of functions marked as willreturn");
>> +STATISTIC(NumNoSync, "Number of functions marked as nosync");
>>     static cl::opt<bool> EnableNonnullArgPropagation(
>>       "enable-nonnull-arg-prop", cl::init(true), cl::Hidden,
>> @@ -1472,6 +1473,28 @@ static bool addWillReturn(const SCCNodeSet 
>> &SCCNodes) {
>>     return Changed;
>>   }
>>   +// Infer the nosync attribute.  For the moment, the inference is 
>> trivial
>> +// and relies on the readnone attribute already being infered. This 
>> will
>> +// be replaced with a more robust implementation in the near future.
>> +static bool addNoSyncAttr(const SCCNodeSet &SCCNodes) {
>> +  bool Changed = false;
>> +
>> +  for (Function *F : SCCNodes) {
>> +    if (!F || F->hasNoSync())
>> +      continue;
>> +
>> +    // readnone + not convergent implies nosync
>> +    if (!F->doesNotAccessMemory() || F->isConvergent())
>> +      continue;
>> +
>> +    F->setNoSync();
>> +    NumNoSync++;
>> +    Changed = true;
>> +  }
>> +
>> +  return Changed;
>> +}
>> +
>>   static SCCNodesResult createSCCNodeSet(ArrayRef<Function *> 
>> Functions) {
>>     SCCNodesResult Res;
>>     Res.HasUnknownCall = false;
>> @@ -1527,6 +1550,8 @@ static bool 
>> deriveAttrsInPostOrder(ArrayRef<Function *> Functions,
>>       Changed |= addNoRecurseAttrs(Nodes.SCCNodes);
>>     }
>>   +  Changed |= addNoSyncAttr(Nodes.SCCNodes);
>> +
>>     return Changed;
>>   }
>>
>> diff  --git 
>> a/llvm/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll 
>> b/llvm/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll
>> index 5bbc86bb69ed2..d0f142b1cef52 100644
>> --- a/llvm/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll
>> +++ b/llvm/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll
>> @@ -72,11 +72,11 @@ define i32 @test3_no(i8* %p) nounwind {
>>   declare void @callee(i32* %p) nounwind
>>   declare void @llvm.memcpy.p0i8.p0i8.i64(i8*, i8*, i64, i1) nounwind
>>   -; CHECK: attributes #0 = { norecurse nounwind readnone willreturn }
>> +; CHECK: attributes #0 = { norecurse nosync nounwind readnone 
>> willreturn }
>>   ; CHECK: attributes #1 = { nofree norecurse nounwind willreturn 
>> writeonly }
>>   ; CHECK: attributes #2 = { nounwind readonly }
>>   ; CHECK: attributes #3 = { nounwind }
>> -; CHECK: attributes #4 = { nounwind readnone willreturn }
>> +; CHECK: attributes #4 = { nosync nounwind readnone willreturn }
>>   ; CHECK: attributes #5 = { nofree nounwind willreturn }
>>   ; CHECK: attributes #6 = { nofree norecurse nounwind willreturn }
>>   ; CHECK: attributes #7 = { argmemonly nofree nosync nounwind 
>> willreturn }
>>
>> diff  --git a/llvm/test/Other/cgscc-devirt-iteration.ll 
>> b/llvm/test/Other/cgscc-devirt-iteration.ll
>> index 9a5a2a79d65fb..651b7f3b28539 100644
>> --- a/llvm/test/Other/cgscc-devirt-iteration.ll
>> +++ b/llvm/test/Other/cgscc-devirt-iteration.ll
>> @@ -28,7 +28,7 @@ declare void @unknown()
>>     define void @test1() {
>>   ; BEFORE-NOT: Function Attrs
>> -; AFTER: Function Attrs: readnone
>> +; AFTER: Function Attrs: nosync readnone
>>   ; CHECK-LABEL: define void @test1()
>>   entry:
>>     %fptr = alloca void ()*
>> @@ -57,7 +57,7 @@ declare void @readnone_with_arg(void ()**) readnone
>>   define void @test2_a(void ()** %ignore) {
>>   ; BEFORE-NOT: Function Attrs
>>   ; AFTER1: Function Attrs: readonly
>> -; AFTER2: Function Attrs: readnone
>> +; AFTER2: Function Attrs: nosync readnone
>>   ; BEFORE: define void @test2_a(void ()** %ignore)
>>   ; AFTER: define void @test2_a(void ()** readnone %ignore)
>>   entry:
>> @@ -78,7 +78,7 @@ entry:
>>   define void @test2_b() {
>>   ; BEFORE-NOT: Function Attrs
>>   ; AFTER1: Function Attrs: readonly
>> -; AFTER2: Function Attrs: readnone
>> +; AFTER2: Function Attrs: nosync readnone
>>   ; CHECK-LABEL: define void @test2_b()
>>   entry:
>>     %f2ptr = alloca void ()*
>>
>> diff  --git a/llvm/test/Other/cgscc-iterate-function-mutation.ll 
>> b/llvm/test/Other/cgscc-iterate-function-mutation.ll
>> index 6689639311bd0..470f9055ced70 100644
>> --- a/llvm/test/Other/cgscc-iterate-function-mutation.ll
>> +++ b/llvm/test/Other/cgscc-iterate-function-mutation.ll
>> @@ -1,8 +1,8 @@
>>   ; RUN: opt -aa-pipeline=basic-aa 
>> -passes='cgscc(function-attrs,function(simplify-cfg))' -S < %s | 
>> FileCheck %s
>>   -declare void @readnone() readnone
>> +declare void @readnone() nosync readnone
>>   declare void @unknown()
>> -declare void @reference_function_pointer(void()*) readnone
>> +declare void @reference_function_pointer(void()*) nosync readnone
>>     ; The @test1_* set of functions checks that when we mutate 
>> functions with
>>   ; simplify-cfg to delete call edges and this ends up splitting both 
>> the SCCs
>> @@ -338,4 +338,4 @@ exit:
>>     ret void
>>   }
>>   -; CHECK: attributes #0 = { readnone }
>> +; CHECK: attributes #0 = { nosync readnone }
>>
>> diff  --git a/llvm/test/Other/cgscc-observe-devirt.ll 
>> b/llvm/test/Other/cgscc-observe-devirt.ll
>> index 3b35f0edc1206..67d630b23a332 100644
>> --- a/llvm/test/Other/cgscc-observe-devirt.ll
>> +++ b/llvm/test/Other/cgscc-observe-devirt.ll
>> @@ -10,7 +10,7 @@
>>   ; without requiring the outer manager to iterate doesn't break any 
>> invariant.
>>   ; RUN: opt -aa-pipeline=basic-aa 
>> -passes='cgscc(function-attrs,function(gvn),function-attrs)' -S < %s 
>> | FileCheck %s --check-prefix=AFTER
>>   -declare void @readnone() readnone
>> +declare void @readnone() nosync readnone
>>   declare void @unknown()
>>     ; The @test1_* checks that if we refine an indirect call to a 
>> direct call and
>> @@ -103,4 +103,4 @@ define void @test2_b3() {
>>     ret void
>>   }
>>   -; CHECK: attributes #0 = { readnone }
>> +; CHECK: attributes #0 = { nosync readnone }
>>
>> diff  --git a/llvm/test/Transforms/FunctionAttrs/atomic.ll 
>> b/llvm/test/Transforms/FunctionAttrs/atomic.ll
>> index 313c54b5ed3ef..3208595684fc7 100644
>> --- a/llvm/test/Transforms/FunctionAttrs/atomic.ll
>> +++ b/llvm/test/Transforms/FunctionAttrs/atomic.ll
>> @@ -20,5 +20,5 @@ entry:
>>     ret i32 %r
>>   }
>>   -; CHECK: attributes #0 = { norecurse nounwind readnone ssp uwtable 
>> willreturn }
>> +; CHECK: attributes #0 = { norecurse nosync nounwind readnone ssp 
>> uwtable willreturn }
>>   ; CHECK: attributes #1 = { nofree norecurse nounwind ssp uwtable 
>> willreturn }
>>
>> diff  --git 
>> a/llvm/test/Transforms/FunctionAttrs/incompatible_fn_attrs.ll 
>> b/llvm/test/Transforms/FunctionAttrs/incompatible_fn_attrs.ll
>> index 4701de3f2e54b..e913aca20c58e 100644
>> --- a/llvm/test/Transforms/FunctionAttrs/incompatible_fn_attrs.ll
>> +++ b/llvm/test/Transforms/FunctionAttrs/incompatible_fn_attrs.ll
>> @@ -28,5 +28,5 @@ entry:
>>   attributes #0 = { argmemonly }
>>   attributes #1 = { inaccessiblememonly }
>>   attributes #2 = { inaccessiblemem_or_argmemonly }
>> -; CHECK: attributes #0 = { norecurse nounwind readnone willreturn }
>> +; CHECK: attributes #0 = { norecurse nosync nounwind readnone 
>> willreturn }
>>   ; CHECK-NOT: attributes
>>
>> diff  --git a/llvm/test/Transforms/FunctionAttrs/nofree-attributor.ll 
>> b/llvm/test/Transforms/FunctionAttrs/nofree-attributor.ll
>> index ef9d086f8f17a..ce33b4c3738cc 100644
>> --- a/llvm/test/Transforms/FunctionAttrs/nofree-attributor.ll
>> +++ b/llvm/test/Transforms/FunctionAttrs/nofree-attributor.ll
>> @@ -12,7 +12,7 @@ declare void @_ZdaPv(i8*) local_unnamed_addr #2
>>       ; TEST 1 (positive case)
>> -; FNATTR: Function Attrs: noinline norecurse nounwind readnone uwtable
>> +; FNATTR: Function Attrs: noinline norecurse nosync nounwind 
>> readnone uwtable
>>   ; FNATTR-NEXT: define void @only_return()
>>   define void @only_return() #0 {
>>       ret void
>> @@ -78,14 +78,14 @@ end:
>>   ; }
>>     -; FNATTR: Function Attrs: noinline nounwind readnone uwtable
>> +; FNATTR: Function Attrs: noinline nosync nounwind readnone uwtable
>>   ; FNATTR-NEXT: define void @mutual_recursion1()
>>   define void @mutual_recursion1() #0 {
>>     call void @mutual_recursion2()
>>     ret void
>>   }
>>   -; FNATTR: Function Attrs: noinline nounwind readnone uwtable
>> +; FNATTR: Function Attrs: noinline nosync nounwind readnone uwtable
>>   ; FNATTR-NEXT: define void @mutual_recursion2()
>>   define void @mutual_recursion2() #0 {
>>     call void @mutual_recursion1()
>> @@ -132,7 +132,7 @@ define noalias i8* @call_realloc(i8* nocapture 
>> %0, i64 %1) local_unnamed_addr #0
>>   ; FNATTR-NEXT: declare void @nofree_function()
>>   declare void @nofree_function() nofree readnone #0
>>   -; FNATTR: Function Attrs: noinline nounwind readnone uwtable
>> +; FNATTR: Function Attrs: noinline nosync nounwind readnone uwtable
>>   ; FNATTR-NEXT: define void @call_nofree_function()
>>   define void @call_nofree_function() #0 {
>>       tail call void @nofree_function()
>> @@ -168,7 +168,7 @@ define void @call_both() #0 {
>>     ; TEST 10 (positive case)
>>   ; Call intrinsic function
>> -; FNATTRS: Function Attrs: noinline readnone speculatable
>> +; FNATTRS: Function Attrs: noinline nosync readnone speculatable
>>   ; FNATTRS-NEXT: declare float @llvm.floor.f32(float %0)
>>   declare float @llvm.floor.f32(float)
>>
>> diff  --git a/llvm/test/Transforms/FunctionAttrs/norecurse.ll 
>> b/llvm/test/Transforms/FunctionAttrs/norecurse.ll
>> index cc48dda663c5e..f5af6406e2a43 100644
>> --- a/llvm/test/Transforms/FunctionAttrs/norecurse.ll
>> +++ b/llvm/test/Transforms/FunctionAttrs/norecurse.ll
>> @@ -2,7 +2,7 @@
>>   ; RUN: opt < %s -aa-pipeline=basic-aa 
>> -passes='cgscc(function-attrs),rpo-function-attrs' -S | FileCheck %s
>>     ; CHECK: Function Attrs
>> -; CHECK-SAME: norecurse nounwind readnone
>> +; CHECK-SAME: norecurse nosync nounwind readnone
>>   ; CHECK-NEXT: define i32 @leaf()
>>   define i32 @leaf() {
>>     ret i32 1
>> @@ -61,7 +61,7 @@ define void @intrinsic(i8* %dest, i8* %src, i32 
>> %len) {
>>   declare void @llvm.memcpy.p0i8.p0i8.i32(i8*, i8*, i32, i1)
>>     ; CHECK: Function Attrs
>> -; CHECK-SAME: norecurse readnone
>> +; CHECK-SAME: norecurse nosync readnone
>>   ; FIXME: missing "norecurse"
>>   ; CHECK-NEXT: define internal i32 @called_by_norecurse()
>>   define internal i32 @called_by_norecurse() {
>> @@ -76,7 +76,7 @@ define void @m() norecurse {
>>   }
>>     ; CHECK: Function Attrs
>> -; CHECK-SAME: norecurse readnone
>> +; CHECK-SAME: norecurse nosync readnone
>>   ; FIXME: missing "norecurse"
>>   ; CHECK-NEXT: define internal i32 @called_by_norecurse_indirectly()
>>   define internal i32 @called_by_norecurse_indirectly() {
>>
>> diff  --git a/llvm/test/Transforms/FunctionAttrs/nosync.ll 
>> b/llvm/test/Transforms/FunctionAttrs/nosync.ll
>> index 8d578e6b67fc7..28eb51e9df0cd 100644
>> --- a/llvm/test/Transforms/FunctionAttrs/nosync.ll
>> +++ b/llvm/test/Transforms/FunctionAttrs/nosync.ll
>> @@ -4,7 +4,7 @@
>>     ; Base case, empty function
>>   define void @test1() {
>> -; CHECK: Function Attrs: norecurse nounwind readnone willreturn
>> +; CHECK: Function Attrs: norecurse nosync nounwind readnone willreturn
>>   ; CHECK-LABEL: @test1(
>>   ; CHECK-NEXT:    ret void
>>   ;
>> @@ -13,7 +13,7 @@ define void @test1() {
>>     ; Show the bottom up walk
>>   define void @test2() {
>> -; CHECK: Function Attrs: norecurse nounwind readnone willreturn
>> +; CHECK: Function Attrs: norecurse nosync nounwind readnone willreturn
>>   ; CHECK-LABEL: @test2(
>>   ; CHECK-NEXT:    call void @test1()
>>   ; CHECK-NEXT:    ret void
>> @@ -36,7 +36,7 @@ define void @test3() convergent {
>>   }
>>     define i32 @test4(i32 %a, i32 %b) {
>> -; CHECK: Function Attrs: norecurse nounwind readnone willreturn
>> +; CHECK: Function Attrs: norecurse nosync nounwind readnone willreturn
>>   ; CHECK-LABEL: @test4(
>>   ; CHECK-NEXT:    [[ADD:%.*]] = add i32 [[A:%.*]], [[B:%.*]]
>>   ; CHECK-NEXT:    ret i32 [[A]]
>>
>> diff  --git a/llvm/test/Transforms/FunctionAttrs/nounwind.ll 
>> b/llvm/test/Transforms/FunctionAttrs/nounwind.ll
>> index 57518f4870cc6..6a667cf73b1e7 100644
>> --- a/llvm/test/Transforms/FunctionAttrs/nounwind.ll
>> +++ b/llvm/test/Transforms/FunctionAttrs/nounwind.ll
>> @@ -1,14 +1,14 @@
>>   ; RUN: opt < %s -function-attrs -S | FileCheck %s
>>     ; TEST 1
>> -; CHECK: Function Attrs: norecurse nounwind readnone
>> +; CHECK: Function Attrs: norecurse nosync nounwind readnone
>>   ; CHECK-NEXT: define i32 @foo1()
>>   define i32 @foo1() {
>>     ret i32 1
>>   }
>>     ; TEST 2
>> -; CHECK: Function Attrs: nounwind readnone
>> +; CHECK: Function Attrs: nosync nounwind readnone
>>   ; CHECK-NEXT: define i32 @scc1_foo()
>>   define i32 @scc1_foo() {
>>     %1 = call i32 @scc1_bar()
>> @@ -17,7 +17,7 @@ define i32 @scc1_foo() {
>>       ; TEST 3
>> -; CHECK: Function Attrs: nounwind readnone
>> +; CHECK: Function Attrs: nosync nounwind readnone
>>   ; CHECK-NEXT: define i32 @scc1_bar()
>>   define i32 @scc1_bar() {
>>     %1 = call i32 @scc1_foo()
>>
>> diff  --git a/llvm/test/Transforms/FunctionAttrs/optnone.ll 
>> b/llvm/test/Transforms/FunctionAttrs/optnone.ll
>> index 9455a2ae40a01..850142762140a 100644
>> --- a/llvm/test/Transforms/FunctionAttrs/optnone.ll
>> +++ b/llvm/test/Transforms/FunctionAttrs/optnone.ll
>> @@ -20,6 +20,6 @@ declare i8 @strlen(i8*) noinline optnone
>>   ; CHECK: (i8*) #1
>>     ; CHECK-LABEL: attributes #0
>> -; CHECK: = { norecurse nounwind readnone willreturn }
>> +; CHECK: = { norecurse nosync nounwind readnone willreturn }
>>   ; CHECK-LABEL: attributes #1
>>   ; CHECK: = { noinline optnone }
>>
>> diff  --git a/llvm/test/Transforms/Inline/cgscc-update.ll 
>> b/llvm/test/Transforms/Inline/cgscc-update.ll
>> index b251a5d070c6e..024d57a13d8fc 100644
>> --- a/llvm/test/Transforms/Inline/cgscc-update.ll
>> +++ b/llvm/test/Transforms/Inline/cgscc-update.ll
>> @@ -27,7 +27,7 @@ entry:
>>   }
>>     ; This function should have had 'readnone' deduced for its SCC.
>> -; CHECK: Function Attrs: noinline nounwind readnone
>> +; CHECK: Function Attrs: noinline nosync nounwind readnone
>>   ; CHECK-NEXT: define void @test1_g()
>>   define void @test1_g() noinline {
>>   entry:
>> @@ -36,7 +36,7 @@ entry:
>>   }
>>     ; This function should have had 'readnone' deduced for its SCC.
>> -; CHECK: Function Attrs: noinline nounwind readnone
>> +; CHECK: Function Attrs: noinline nosync nounwind readnone
>>   ; CHECK-NEXT: define void @test1_h()
>>   define void @test1_h() noinline {
>>   entry:
>> @@ -59,7 +59,7 @@ entry:
>>   }
>>     ; This function should have had 'readnone' deduced for its SCC.
>> -; CHECK: Function Attrs: noinline nounwind readnone
>> +; CHECK: Function Attrs: noinline nosync nounwind readnone
>>   ; CHECK-NEXT: define void @test2_g()
>>   define void @test2_g() noinline {
>>   entry:
>> @@ -69,7 +69,7 @@ entry:
>>   }
>>     ; This function should have had 'readnone' deduced for its SCC.
>> -; CHECK: Function Attrs: noinline nounwind readnone
>> +; CHECK: Function Attrs: noinline nosync nounwind readnone
>>   ; CHECK-NEXT: define void @test2_h()
>>   define void @test2_h() noinline {
>>   entry:
>> @@ -152,7 +152,7 @@ exit:
>>   ; form a new SCC and should use that can deduce precise function 
>> attrs.
>>     ; This function should have had 'readnone' deduced for its SCC.
>> -; CHECK: Function Attrs: noinline nounwind readnone
>> +; CHECK: Function Attrs: noinline nosync nounwind readnone
>>   ; CHECK-NEXT: define void @test4_f1()
>>   define void @test4_f1() noinline {
>>   entry:
>> @@ -175,7 +175,7 @@ entry:
>>   }
>>     ; This function should have had 'readnone' deduced for its SCC.
>> -; CHECK: Function Attrs: noinline nounwind readnone
>> +; CHECK: Function Attrs: noinline nosync nounwind readnone
>>   ; CHECK-NEXT: define void @test4_h()
>>   define void @test4_h() noinline {
>>   entry:
>>
>>
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