8aae191cb6
Emil Tsalapatis from Meta reported such a case where 'may_goto 0' insn is generated by clang compiler. But 'may_goto 0' insn is actually a no-op so it makes sense to remove that in llvm. The patch is also able to handle the following code pattern ``` ... may_goto 2 may_goto 1 may_goto 0 ... ``` where three may_goto insns can all be removed. --------- Co-authored-by: Yonghong Song <yonghong.song@linux.dev>
28 lines
1.1 KiB
LLVM
28 lines
1.1 KiB
LLVM
; RUN: llc -mtriple=bpfel -mcpu=v3 -filetype=obj -o - %s | llvm-objdump --no-show-raw-insn -d - | FileCheck %s
|
|
|
|
@j = dso_local local_unnamed_addr global i32 0, align 4
|
|
|
|
define dso_local noundef i32 @foo() local_unnamed_addr {
|
|
entry:
|
|
callbr void asm sideeffect "may_goto $0", "!i"()
|
|
to label %for.body [label %for.cond.cleanup]
|
|
|
|
for.cond.cleanup: ; preds = %for.body.2, %for.body.2, %for.body.1, %for.body, %entry
|
|
ret i32 0
|
|
|
|
for.body: ; preds = %entry
|
|
callbr void asm sideeffect "may_goto $0", "!i"()
|
|
to label %for.body.1 [label %for.cond.cleanup]
|
|
|
|
for.body.1: ; preds = %for.body
|
|
callbr void asm sideeffect "may_goto $0", "!i"()
|
|
to label %for.body.2 [label %for.cond.cleanup]
|
|
|
|
for.body.2: ; preds = %for.body.1
|
|
callbr void asm sideeffect "may_goto $0", "!i"()
|
|
to label %for.cond.cleanup [label %for.cond.cleanup]
|
|
}
|
|
|
|
; CHECK: 0: w0 = 0x0
|
|
; CHECK-NEXT: 1: exit
|