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[X86] Add test cases for the patterns used by __builtin_ffs. 

We previously had tests for "__builtin_ffs + 5", but the SelectinoDAG without an extra addition came out slightly different.

llvm-svn: 338612
This commit is contained in:
Craig Topper 2018-08-01 18:38:43 +00:00
parent 95d8c464d8
commit ffb8eb30ff
1 changed files with 49 additions and 0 deletions
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49
llvm/test/CodeGen/X86/dagcombine-select.ll
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@ -378,3 +378,52 @@ define i32 @cttz_32_ne_select(i32 %v) nounwind {
%add = select i1 %tobool, i32 %.op, i32 5
ret i32 %add
}
; This matches the pattern emitted for __builtin_ffs
define i32 @cttz_32_eq_select_ffs(i32 %v) nounwind {
; NOBMI-LABEL: cttz_32_eq_select_ffs:
; NOBMI: # %bb.0:
; NOBMI-NEXT: bsfl %edi, %eax
; NOBMI-NEXT: incl %eax
; NOBMI-NEXT: testl %edi, %edi
; NOBMI-NEXT: cmovel %edi, %eax
; NOBMI-NEXT: retq
;
; BMI-LABEL: cttz_32_eq_select_ffs:
; BMI: # %bb.0:
; BMI-NEXT: tzcntl %edi, %eax
; BMI-NEXT: incl %eax
; BMI-NEXT: testl %edi, %edi
; BMI-NEXT: cmovel %edi, %eax
; BMI-NEXT: retq
%cnt = tail call i32 @llvm.cttz.i32(i32 %v, i1 true)
%tobool = icmp eq i32 %v, 0
%.op = add nuw nsw i32 %cnt, 1
%add = select i1 %tobool, i32 0, i32 %.op
ret i32 %add
}
define i32 @cttz_32_ne_select_ffs(i32 %v) nounwind {
; NOBMI-LABEL: cttz_32_ne_select_ffs:
; NOBMI: # %bb.0:
; NOBMI-NEXT: bsfl %edi, %eax
; NOBMI-NEXT: incl %eax
; NOBMI-NEXT: testl %edi, %edi
; NOBMI-NEXT: cmovel %edi, %eax
; NOBMI-NEXT: retq
;
; BMI-LABEL: cttz_32_ne_select_ffs:
; BMI: # %bb.0:
; BMI-NEXT: tzcntl %edi, %eax
; BMI-NEXT: incl %eax
; BMI-NEXT: testl %edi, %edi
; BMI-NEXT: cmovel %edi, %eax
; BMI-NEXT: retq
%cnt = tail call i32 @llvm.cttz.i32(i32 %v, i1 true)
%tobool = icmp ne i32 %v, 0
%.op = add nuw nsw i32 %cnt, 1
%add = select i1 %tobool, i32 %.op, i32 0
ret i32 %add
}