2a721374ae
Following some recent discussions, this changes the representation
of callbrs in IR. The current blockaddress arguments are replaced
with `!` label constraints that refer directly to callbr indirect
destinations:
; Before:
%res = callbr i8* asm "", "=r,r,i"(i8* %x, i8* blockaddress(@test8, %foo))
to label %asm.fallthrough [label %foo]
; After:
%res = callbr i8* asm "", "=r,r,!i"(i8* %x)
to label %asm.fallthrough [label %foo]
The benefit of this is that we can easily update the successors of
a callbr, without having to worry about also updating blockaddress
references. This should allow us to remove some limitations:
* Allow unrolling/peeling/rotation of callbr, or any other
clone-based optimizations
(https://github.com/llvm/llvm-project/issues/41834)
* Allow duplicate successors
(https://github.com/llvm/llvm-project/issues/45248)
This is just the IR representation change though, I will follow up
with patches to remove limtations in various transformation passes
that are no longer needed.
Differential Revision: https://reviews.llvm.org/D129288
40 lines
1.1 KiB
LLVM
40 lines
1.1 KiB
LLVM
; RUN: opt %loadPolly -polly-detect -polly-detect-track-failures -disable-output -pass-remarks-missed=polly-detect < %s 2>&1 | FileCheck %s --check-prefix=REMARK
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; RUN: opt %loadPolly -polly-detect -polly-detect-track-failures -disable-output -stats < %s 2>&1 | FileCheck %s --check-prefix=STAT
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; REQUIRES: asserts
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; REMARK: Branch from indirect terminator.
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; STAT: 1 polly-detect - Number of rejected regions: Branch from indirect terminator
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target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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define void @func(i32 %n, double* noalias nonnull %A) {
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entry:
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callbr void asm sideeffect "", "!i,~{dirflag},~{fpsr},~{flags}"() #1
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to label %fallthrough [label %for]
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fallthrough:
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br label %for
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for:
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%j = phi i32 [0, %entry], [0, %fallthrough], [%j.inc, %inc]
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%j.cmp = icmp slt i32 %j, %n
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br i1 %j.cmp, label %body, label %exit
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body:
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store double 42.0, double* %A
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br label %inc
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inc:
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%j.inc = add nuw nsw i32 %j, 1
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br label %for
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exit:
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br label %return
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return:
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ret void
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}
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