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
83 lines
2.8 KiB
LLVM
83 lines
2.8 KiB
LLVM
; RUN: split-file %s %t
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; RUN: not llvm-as < %t/parse-fail.ll 2>&1 | FileCheck %s --check-prefix=CHECK-PARSE-FAIL
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; RUN: not llvm-as < %t/input-before-output.ll 2>&1 | FileCheck %s --check-prefix=CHECK-INPUT-BEFORE-OUTPUT
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; RUN: not llvm-as < %t/input-after-clobber.ll 2>&1 | FileCheck %s --check-prefix=CHECK-INPUT-AFTER-CLOBBER
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; RUN: not llvm-as < %t/must-return-void.ll 2>&1 | FileCheck %s --check-prefix=CHECK-MUST-RETURN-VOID
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; RUN: not llvm-as < %t/cannot-be-struct.ll 2>&1 | FileCheck %s --check-prefix=CHECK-CANNOT-BE-STRUCT
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; RUN: not llvm-as < %t/incorrect-struct-elements.ll 2>&1 | FileCheck %s --check-prefix=CHECK-INCORRECT-STRUCT-ELEMENTS
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; RUN: not llvm-as < %t/incorrect-arg-num.ll 2>&1 | FileCheck %s --check-prefix=CHECK-INCORRECT-ARG-NUM
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; RUN: not llvm-as < %t/label-after-clobber.ll 2>&1 | FileCheck %s --check-prefix=CHECK-LABEL-AFTER-CLOBBER
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; RUN: not llvm-as < %t/output-after-label.ll 2>&1 | FileCheck %s --check-prefix=CHECK-OUTPUT-AFTER-LABEL
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;--- parse-fail.ll
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; CHECK-PARSE-FAIL: failed to parse constraints
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define void @foo() {
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; "~x{21}" is not a valid clobber constraint.
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call void asm sideeffect "mov x0, #42", "~{x0},~{x19},~x{21}"()
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ret void
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}
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;--- input-before-output.ll
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; CHECK-INPUT-BEFORE-OUTPUT: output constraint occurs after input, clobber or label constraint
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define void @foo() {
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call void asm sideeffect "mov x0, #42", "r,=r"()
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ret void
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}
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;--- input-after-clobber.ll
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; CHECK-INPUT-AFTER-CLOBBER: input constraint occurs after clobber constraint
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define void @foo() {
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call void asm sideeffect "mov x0, #42", "~{x0},r"()
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ret void
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}
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;--- must-return-void.ll
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; CHECK-MUST-RETURN-VOID: inline asm without outputs must return void
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define void @foo() {
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call i32 asm sideeffect "mov x0, #42", ""()
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ret void
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}
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;--- cannot-be-struct.ll
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; CHECK-CANNOT-BE-STRUCT: inline asm with one output cannot return struct
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define void @foo() {
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call { i32 } asm sideeffect "mov x0, #42", "=r"()
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ret void
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}
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;--- incorrect-struct-elements.ll
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; CHECK-INCORRECT-STRUCT-ELEMENTS: number of output constraints does not match number of return struct elements
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define void @foo() {
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call { i32 } asm sideeffect "mov x0, #42", "=r,=r"()
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ret void
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}
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;--- incorrect-arg-num.ll
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; CHECK-INCORRECT-ARG-NUM: number of input constraints does not match number of parameters
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define void @foo() {
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call void asm sideeffect "mov x0, #42", "r"()
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ret void
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}
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;--- label-after-clobber.ll
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; CHECK-LABEL-AFTER-CLOBBER: label constraint occurs after clobber constraint
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define void @foo() {
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callbr void asm sideeffect "", "~{flags},!i"()
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to label %1 [label %2]
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1:
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ret void
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2:
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ret void
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}
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;--- output-after-label.ll
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; CHECK-OUTPUT-AFTER-LABEL: output constraint occurs after input, clobber or label constraint
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define void @foo() {
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%res = callbr i32 asm sideeffect "", "!i,=r,~{flags}"()
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to label %1 [label %2]
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1:
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ret void
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2:
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ret void
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}
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