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[x86] add tests to show missing demanded bits analysis; NFC 

llvm-svn: 288515
This commit is contained in:
Sanjay Patel 2016-12-02 17:48:48 +00:00
parent 2df9963fe3
commit 91d1ed5ee6
1 changed files with 53 additions and 0 deletions
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53
llvm/test/CodeGen/X86/not-and-simplify.ll Normal file
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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=-bmi | FileCheck %s --check-prefix=NO_BMI
; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=+bmi | FileCheck %s --check-prefix=BMI
; Clear high bits via shift, set them with xor (not), then mask them off.
define i32 @shrink_xor_constant1(i32 %x) {
; NO_BMI-LABEL: shrink_xor_constant1:
; NO_BMI: # BB#0:
; NO_BMI-NEXT: shrl $31, %edi
; NO_BMI-NEXT: notl %edi
; NO_BMI-NEXT: andl $1, %edi
; NO_BMI-NEXT: movl %edi, %eax
; NO_BMI-NEXT: retq
;
; BMI-LABEL: shrink_xor_constant1:
; BMI: # BB#0:
; BMI-NEXT: shrl $31, %edi
; BMI-NEXT: movl $1, %eax
; BMI-NEXT: andnl %eax, %edi, %eax
; BMI-NEXT: retq
;
%sh = lshr i32 %x, 31
%not = xor i32 %sh, -1
%and = and i32 %not, 1
ret i32 %and
}
; Clear low bits via shift, set them with xor (not), then mask them off.
define i8 @shrink_xor_constant2(i8 %x) {
; NO_BMI-LABEL: shrink_xor_constant2:
; NO_BMI: # BB#0:
; NO_BMI-NEXT: shlb $5, %dil
; NO_BMI-NEXT: notb %dil
; NO_BMI-NEXT: andb $-32, %dil
; NO_BMI-NEXT: movl %edi, %eax
; NO_BMI-NEXT: retq
;
; BMI-LABEL: shrink_xor_constant3:
; BMI: # BB#0:
; BMI-NEXT: shlb $5, %dil
; BMI-NEXT: notb %dil
; BMI-NEXT: andb $-32, %dil
; BMI-NEXT: movl %edi, %eax
; BMI-NEXT: retq
;
%sh = shl i8 %x, 5
%not = xor i8 %sh, -1
%and = and i8 %not, 224 ; 0xE0
ret i8 %and
}