6660fd0f95
Summary:
This was motivated by absence of PrunEH functionality in new PM.
It was decided that a proper way to do PruneEH is to add NoUnwind inference
into PostOrderFunctionAttrs and then perform normal SimplifyCFG on top.
This change generalizes attribute handling implemented for (a removal of)
Convergent attribute, by introducing a generic builder-like class
AttributeInferer
It registers all the attribute inference requests, storing per-attribute
predicates into a vector, and then goes through an SCC Node, scanning all
the instructions for not breaking attribute assumptions.
The main idea is that as soon all the instructions from all the functions
of SCC Node conform to attribute assumptions then we are free to infer
the attribute as set for all the functions of SCC Node.
It handles two distinct cases of attributes:
- those that might break due to derefinement of the function code
for these attributes we are allowed to apply inference only if all the
functions are "exact definitions". Example - NoUnwind.
- those that do not care about derefinement
for these attributes we are allowed to apply inference as soon as we see
any function definition. Example - removal of Convergent attribute.
Also in this commit:
* Converted all the FunctionAttrs tests to use FileCheck and added new-PM
invocations to them
* FunctionAttrs/convergent.ll test demonstrates a difference in behavior between
new and old PM implementations. Marked with FIXME.
* PruneEH tests were converted to new-PM as well, using function-attrs+simplify-cfg
combo as intended
* some of "other" tests were updated since function-attrs now infers 'nounwind'
even for old PM pipeline
* -disable-nounwind-inference hidden option added as a possible workaround for a supposedly
rare case when nounwind being inferred by default presents a problem
Reviewers: chandlerc, jlebar
Reviewed By: jlebar
Subscribers: eraman, llvm-commits
Differential Revision: https://reviews.llvm.org/D44415
llvm-svn: 328377
223 lines
5.9 KiB
LLVM
223 lines
5.9 KiB
LLVM
; RUN: opt < %s -functionattrs -S | FileCheck %s
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; RUN: opt < %s -passes=function-attrs -S | FileCheck %s
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@g = global i32* null ; <i32**> [#uses=1]
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; CHECK: define i32* @c1(i32* readnone returned %q)
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define i32* @c1(i32* %q) {
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ret i32* %q
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}
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; CHECK: define void @c2(i32* %q)
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; It would also be acceptable to mark %q as readnone. Update @c3 too.
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define void @c2(i32* %q) {
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store i32* %q, i32** @g
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ret void
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}
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; CHECK: define void @c3(i32* %q)
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define void @c3(i32* %q) {
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call void @c2(i32* %q)
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ret void
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}
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; CHECK: define i1 @c4(i32* %q, i32 %bitno)
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define i1 @c4(i32* %q, i32 %bitno) {
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%tmp = ptrtoint i32* %q to i32
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%tmp2 = lshr i32 %tmp, %bitno
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%bit = trunc i32 %tmp2 to i1
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br i1 %bit, label %l1, label %l0
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l0:
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ret i1 0 ; escaping value not caught by def-use chaining.
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l1:
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ret i1 1 ; escaping value not caught by def-use chaining.
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}
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@lookup_table = global [2 x i1] [ i1 0, i1 1 ]
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; CHECK: define i1 @c5(i32* %q, i32 %bitno)
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define i1 @c5(i32* %q, i32 %bitno) {
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%tmp = ptrtoint i32* %q to i32
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%tmp2 = lshr i32 %tmp, %bitno
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%bit = and i32 %tmp2, 1
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; subtle escape mechanism follows
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%lookup = getelementptr [2 x i1], [2 x i1]* @lookup_table, i32 0, i32 %bit
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%val = load i1, i1* %lookup
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ret i1 %val
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}
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declare void @throw_if_bit_set(i8*, i8) readonly
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; CHECK: define i1 @c6(i8* readonly %q, i8 %bit)
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define i1 @c6(i8* %q, i8 %bit) personality i32 (...)* @__gxx_personality_v0 {
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invoke void @throw_if_bit_set(i8* %q, i8 %bit)
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to label %ret0 unwind label %ret1
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ret0:
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ret i1 0
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ret1:
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%exn = landingpad {i8*, i32}
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cleanup
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ret i1 1
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}
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declare i32 @__gxx_personality_v0(...)
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define i1* @lookup_bit(i32* %q, i32 %bitno) readnone nounwind {
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%tmp = ptrtoint i32* %q to i32
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%tmp2 = lshr i32 %tmp, %bitno
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%bit = and i32 %tmp2, 1
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%lookup = getelementptr [2 x i1], [2 x i1]* @lookup_table, i32 0, i32 %bit
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ret i1* %lookup
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}
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; CHECK: define i1 @c7(i32* readonly %q, i32 %bitno)
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define i1 @c7(i32* %q, i32 %bitno) {
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%ptr = call i1* @lookup_bit(i32* %q, i32 %bitno)
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%val = load i1, i1* %ptr
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ret i1 %val
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}
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; CHECK: define i32 @nc1(i32* %q, i32* nocapture %p, i1 %b)
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define i32 @nc1(i32* %q, i32* %p, i1 %b) {
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e:
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br label %l
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l:
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%x = phi i32* [ %p, %e ]
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%y = phi i32* [ %q, %e ]
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%tmp = bitcast i32* %x to i32* ; <i32*> [#uses=2]
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%tmp2 = select i1 %b, i32* %tmp, i32* %y
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%val = load i32, i32* %tmp2 ; <i32> [#uses=1]
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store i32 0, i32* %tmp
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store i32* %y, i32** @g
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ret i32 %val
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}
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; CHECK: define i32 @nc1_addrspace(i32* %q, i32 addrspace(1)* nocapture %p, i1 %b)
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define i32 @nc1_addrspace(i32* %q, i32 addrspace(1)* %p, i1 %b) {
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e:
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br label %l
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l:
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%x = phi i32 addrspace(1)* [ %p, %e ]
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%y = phi i32* [ %q, %e ]
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%tmp = addrspacecast i32 addrspace(1)* %x to i32* ; <i32*> [#uses=2]
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%tmp2 = select i1 %b, i32* %tmp, i32* %y
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%val = load i32, i32* %tmp2 ; <i32> [#uses=1]
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store i32 0, i32* %tmp
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store i32* %y, i32** @g
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ret i32 %val
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}
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; CHECK: define void @nc2(i32* nocapture %p, i32* %q)
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define void @nc2(i32* %p, i32* %q) {
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%1 = call i32 @nc1(i32* %q, i32* %p, i1 0) ; <i32> [#uses=0]
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ret void
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}
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; CHECK: define void @nc3(void ()* nocapture %p)
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define void @nc3(void ()* %p) {
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call void %p()
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ret void
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}
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declare void @external(i8*) readonly nounwind
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; CHECK: define void @nc4(i8* nocapture readonly %p)
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define void @nc4(i8* %p) {
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call void @external(i8* %p)
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ret void
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}
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; CHECK: define void @nc5(void (i8*)* nocapture %f, i8* nocapture %p)
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define void @nc5(void (i8*)* %f, i8* %p) {
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call void %f(i8* %p) readonly nounwind
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call void %f(i8* nocapture %p)
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ret void
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}
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; CHECK: define void @test1_1(i8* nocapture readnone %x1_1, i8* %y1_1)
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; It would be acceptable to add readnone to %y1_1 and %y1_2.
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define void @test1_1(i8* %x1_1, i8* %y1_1) {
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call i8* @test1_2(i8* %x1_1, i8* %y1_1)
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store i32* null, i32** @g
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ret void
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}
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; CHECK: define i8* @test1_2(i8* nocapture readnone %x1_2, i8* returned %y1_2)
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define i8* @test1_2(i8* %x1_2, i8* %y1_2) {
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call void @test1_1(i8* %x1_2, i8* %y1_2)
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store i32* null, i32** @g
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ret i8* %y1_2
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}
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; CHECK: define void @test2(i8* nocapture readnone %x2)
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define void @test2(i8* %x2) {
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call void @test2(i8* %x2)
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store i32* null, i32** @g
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ret void
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}
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; CHECK: define void @test3(i8* nocapture readnone %x3, i8* nocapture readnone %y3, i8* nocapture readnone %z3)
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define void @test3(i8* %x3, i8* %y3, i8* %z3) {
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call void @test3(i8* %z3, i8* %y3, i8* %x3)
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store i32* null, i32** @g
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ret void
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}
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; CHECK: define void @test4_1(i8* %x4_1)
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define void @test4_1(i8* %x4_1) {
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call i8* @test4_2(i8* %x4_1, i8* %x4_1, i8* %x4_1)
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store i32* null, i32** @g
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ret void
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}
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; CHECK: define i8* @test4_2(i8* nocapture readnone %x4_2, i8* readnone returned %y4_2, i8* nocapture readnone %z4_2)
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define i8* @test4_2(i8* %x4_2, i8* %y4_2, i8* %z4_2) {
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call void @test4_1(i8* null)
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store i32* null, i32** @g
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ret i8* %y4_2
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}
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declare i8* @test5_1(i8* %x5_1)
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; CHECK: define void @test5_2(i8* %x5_2)
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define void @test5_2(i8* %x5_2) {
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call i8* @test5_1(i8* %x5_2)
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store i32* null, i32** @g
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ret void
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}
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declare void @test6_1(i8* %x6_1, i8* nocapture %y6_1, ...)
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; CHECK: define void @test6_2(i8* %x6_2, i8* nocapture %y6_2, i8* %z6_2)
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define void @test6_2(i8* %x6_2, i8* %y6_2, i8* %z6_2) {
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call void (i8*, i8*, ...) @test6_1(i8* %x6_2, i8* %y6_2, i8* %z6_2)
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store i32* null, i32** @g
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ret void
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}
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; CHECK: define void @test_cmpxchg(i32* nocapture %p)
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define void @test_cmpxchg(i32* %p) {
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cmpxchg i32* %p, i32 0, i32 1 acquire monotonic
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ret void
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}
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; CHECK: define void @test_cmpxchg_ptr(i32** nocapture %p, i32* %q)
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define void @test_cmpxchg_ptr(i32** %p, i32* %q) {
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cmpxchg i32** %p, i32* null, i32* %q acquire monotonic
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ret void
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}
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; CHECK: define void @test_atomicrmw(i32* nocapture %p)
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define void @test_atomicrmw(i32* %p) {
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atomicrmw add i32* %p, i32 1 seq_cst
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ret void
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}
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; CHECK: define void @test_volatile(i32* %x)
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define void @test_volatile(i32* %x) {
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entry:
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%gep = getelementptr i32, i32* %x, i64 1
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store volatile i32 0, i32* %gep, align 4
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ret void
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}
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