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llvm-project/llvm/test/Transforms/FunctionAttrs/readnone.ll

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Remove conflicting attributes before adding deduced readonly/readnone Summary: In case of functions that have a pointer argument and only pass it to each other, the function attributes pass deduces that the pointer should get the readnone attribute, but fails to remove a readonly attribute that may already have been present. Reviewers: nlewycky Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D9995 llvm-svn: 238152
2015-05-26 03:46:38 +08:00
; RUN: opt < %s -functionattrs -S | FileCheck %s
[PM][FunctionAttrs] add NoUnwind attribute inference to PostOrderFunctionAttrs pass 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
2018-03-24 05:46:16 +08:00
; RUN: opt < %s -passes=function-attrs -S | FileCheck %s
Remove conflicting attributes before adding deduced readonly/readnone Summary: In case of functions that have a pointer argument and only pass it to each other, the function attributes pass deduces that the pointer should get the readnone attribute, but fails to remove a readonly attribute that may already have been present. Reviewers: nlewycky Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D9995 llvm-svn: 238152
2015-05-26 03:46:38 +08:00
; CHECK: define void @bar(i8* nocapture readnone)
define void @bar(i8* readonly) {
call void @foo(i8* %0)
ret void
}
; CHECK: define void @foo(i8* nocapture readnone)
define void @foo(i8* readonly) {
call void @bar(i8* %0)
ret void
}