142 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			142 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; RUN: llc < %s -march=x86-64 -mcpu=yonah | FileCheck %s
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declare i8 @llvm.cttz.i8(i8, i1)
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declare i16 @llvm.cttz.i16(i16, i1)
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declare i32 @llvm.cttz.i32(i32, i1)
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declare i64 @llvm.cttz.i64(i64, i1)
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declare i8 @llvm.ctlz.i8(i8, i1)
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declare i16 @llvm.ctlz.i16(i16, i1)
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declare i32 @llvm.ctlz.i32(i32, i1)
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declare i64 @llvm.ctlz.i64(i64, i1)
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define i8 @cttz_i8(i8 %x)  {
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  %tmp = call i8 @llvm.cttz.i8( i8 %x, i1 true )
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  ret i8 %tmp
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; CHECK-LABEL: cttz_i8:
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; CHECK: bsfl
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; CHECK-NOT: cmov
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; CHECK: ret
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}
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define i16 @cttz_i16(i16 %x)  {
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  %tmp = call i16 @llvm.cttz.i16( i16 %x, i1 true )
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  ret i16 %tmp
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; CHECK-LABEL: cttz_i16:
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; CHECK: bsfw
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; CHECK-NOT: cmov
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; CHECK: ret
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}
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define i32 @cttz_i32(i32 %x)  {
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  %tmp = call i32 @llvm.cttz.i32( i32 %x, i1 true )
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  ret i32 %tmp
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; CHECK-LABEL: cttz_i32:
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; CHECK: bsfl
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; CHECK-NOT: cmov
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; CHECK: ret
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}
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define i64 @cttz_i64(i64 %x)  {
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  %tmp = call i64 @llvm.cttz.i64( i64 %x, i1 true )
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  ret i64 %tmp
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; CHECK-LABEL: cttz_i64:
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; CHECK: bsfq
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; CHECK-NOT: cmov
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; CHECK: ret
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}
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define i8 @ctlz_i8(i8 %x) {
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entry:
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  %tmp2 = call i8 @llvm.ctlz.i8( i8 %x, i1 true )
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  ret i8 %tmp2
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; CHECK-LABEL: ctlz_i8:
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; CHECK: bsrl
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; CHECK-NOT: cmov
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; CHECK: xorl $7,
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; CHECK: ret
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}
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define i16 @ctlz_i16(i16 %x) {
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entry:
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  %tmp2 = call i16 @llvm.ctlz.i16( i16 %x, i1 true )
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  ret i16 %tmp2
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; CHECK-LABEL: ctlz_i16:
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; CHECK: bsrw
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; CHECK-NOT: cmov
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; CHECK: xorl $15,
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; CHECK: ret
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}
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define i32 @ctlz_i32(i32 %x) {
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  %tmp = call i32 @llvm.ctlz.i32( i32 %x, i1 true )
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  ret i32 %tmp
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; CHECK-LABEL: ctlz_i32:
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; CHECK: bsrl
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; CHECK-NOT: cmov
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; CHECK: xorl $31,
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; CHECK: ret
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}
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define i64 @ctlz_i64(i64 %x) {
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  %tmp = call i64 @llvm.ctlz.i64( i64 %x, i1 true )
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  ret i64 %tmp
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; CHECK-LABEL: ctlz_i64:
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; CHECK: bsrq
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; CHECK-NOT: cmov
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; CHECK: xorq $63,
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; CHECK: ret
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}
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define i32 @ctlz_i32_cmov(i32 %n) {
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entry:
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; Generate a cmov to handle zero inputs when necessary.
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; CHECK-LABEL: ctlz_i32_cmov:
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; CHECK: bsrl
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; CHECK: cmov
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; CHECK: xorl $31,
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; CHECK: ret
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  %tmp1 = call i32 @llvm.ctlz.i32(i32 %n, i1 false)
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  ret i32 %tmp1
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}
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define i32 @ctlz_i32_fold_cmov(i32 %n) {
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entry:
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; Don't generate the cmovne when the source is known non-zero (and bsr would
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; not set ZF).
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; rdar://9490949
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; CHECK-LABEL: ctlz_i32_fold_cmov:
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; CHECK: bsrl
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; CHECK-NOT: cmov
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; CHECK: xorl $31,
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; CHECK: ret
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  %or = or i32 %n, 1
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  %tmp1 = call i32 @llvm.ctlz.i32(i32 %or, i1 false)
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  ret i32 %tmp1
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}
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define i32 @ctlz_bsr(i32 %n) {
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entry:
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; Don't generate any xors when a 'ctlz' intrinsic is actually used to compute
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; the most significant bit, which is what 'bsr' does natively.
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; CHECK-LABEL: ctlz_bsr:
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; CHECK: bsrl
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; CHECK-NOT: xorl
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; CHECK: ret
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  %ctlz = call i32 @llvm.ctlz.i32(i32 %n, i1 true)
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  %bsr = xor i32 %ctlz, 31
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  ret i32 %bsr
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}
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define i32 @ctlz_bsr_cmov(i32 %n) {
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entry:
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; Same as ctlz_bsr, but ensure this happens even when there is a potential
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; zero.
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; CHECK-LABEL: ctlz_bsr_cmov:
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; CHECK: bsrl
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; CHECK-NOT: xorl
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; CHECK: ret
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  %ctlz = call i32 @llvm.ctlz.i32(i32 %n, i1 false)
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  %bsr = xor i32 %ctlz, 31
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  ret i32 %bsr
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}
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