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[X86] Add test cases for missed opportunity to use a byte test instruction instead of an xor with 0 in parity patterns.

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If the input to the ctpop fits in 8 bits, we can use the parity
flag from a TEST instruction, but we're currently XORing with 0.
This commit is contained in:
Craig Topper 2020-08-02 00:20:11 -07:00
parent 3819392568
commit ad50e8efd7
1 changed files with 70 additions and 0 deletions
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70
test/CodeGen/X86/parity.ll
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@ -181,5 +181,75 @@ define i8 @parity_32_trunc(i32 %x) {
ret i8 %3
}
define i32 @parity_8_zext(i8 %x) {
; X86-NOPOPCNT-LABEL: parity_8_zext:
; X86-NOPOPCNT: # %bb.0:
; X86-NOPOPCNT-NEXT: movb {{[0-9]+}}(%esp), %cl
; X86-NOPOPCNT-NEXT: xorl %eax, %eax
; X86-NOPOPCNT-NEXT: xorb $0, %cl
; X86-NOPOPCNT-NEXT: setnp %al
; X86-NOPOPCNT-NEXT: retl
;
; X64-NOPOPCNT-LABEL: parity_8_zext:
; X64-NOPOPCNT: # %bb.0:
; X64-NOPOPCNT-NEXT: xorl %eax, %eax
; X64-NOPOPCNT-NEXT: xorb $0, %dil
; X64-NOPOPCNT-NEXT: setnp %al
; X64-NOPOPCNT-NEXT: retq
;
; X86-POPCNT-LABEL: parity_8_zext:
; X86-POPCNT: # %bb.0:
; X86-POPCNT-NEXT: movzbl {{[0-9]+}}(%esp), %eax
; X86-POPCNT-NEXT: popcntl %eax, %eax
; X86-POPCNT-NEXT: andl $1, %eax
; X86-POPCNT-NEXT: retl
;
; X64-POPCNT-LABEL: parity_8_zext:
; X64-POPCNT: # %bb.0:
; X64-POPCNT-NEXT: movzbl %dil, %eax
; X64-POPCNT-NEXT: popcntl %eax, %eax
; X64-POPCNT-NEXT: andl $1, %eax
; X64-POPCNT-NEXT: retq
%a = zext i8 %x to i32
%b = tail call i32 @llvm.ctpop.i32(i32 %a)
%c = and i32 %b, 1
ret i32 %c
}
define i32 @parity_8_mask(i32 %x) {
; X86-NOPOPCNT-LABEL: parity_8_mask:
; X86-NOPOPCNT: # %bb.0:
; X86-NOPOPCNT-NEXT: movb {{[0-9]+}}(%esp), %cl
; X86-NOPOPCNT-NEXT: xorl %eax, %eax
; X86-NOPOPCNT-NEXT: xorb $0, %cl
; X86-NOPOPCNT-NEXT: setnp %al
; X86-NOPOPCNT-NEXT: retl
;
; X64-NOPOPCNT-LABEL: parity_8_mask:
; X64-NOPOPCNT: # %bb.0:
; X64-NOPOPCNT-NEXT: xorl %eax, %eax
; X64-NOPOPCNT-NEXT: xorb $0, %dil
; X64-NOPOPCNT-NEXT: setnp %al
; X64-NOPOPCNT-NEXT: retq
;
; X86-POPCNT-LABEL: parity_8_mask:
; X86-POPCNT: # %bb.0:
; X86-POPCNT-NEXT: movzbl {{[0-9]+}}(%esp), %eax
; X86-POPCNT-NEXT: popcntl %eax, %eax
; X86-POPCNT-NEXT: andl $1, %eax
; X86-POPCNT-NEXT: retl
;
; X64-POPCNT-LABEL: parity_8_mask:
; X64-POPCNT: # %bb.0:
; X64-POPCNT-NEXT: movzbl %dil, %eax
; X64-POPCNT-NEXT: popcntl %eax, %eax
; X64-POPCNT-NEXT: andl $1, %eax
; X64-POPCNT-NEXT: retq
%a = and i32 %x, 255
%b = tail call i32 @llvm.ctpop.i32(i32 %a)
%c = and i32 %b, 1
ret i32 %c
}
declare i32 @llvm.ctpop.i32(i32 %x)
declare i64 @llvm.ctpop.i64(i64 %x)