55 lines
		
	
	
		
			1.1 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			55 lines
		
	
	
		
			1.1 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; RUN: opt < %s -instcombine -S | FileCheck %s
 | 
						|
 | 
						|
target triple = "x86_64-unknown-freebsd11.0"
 | 
						|
 | 
						|
define i32 @myfls() {
 | 
						|
; CHECK-LABEL: @myfls(
 | 
						|
; CHECK-NEXT:    ret i32 6
 | 
						|
;
 | 
						|
  %call = call i32 @fls(i32 42)
 | 
						|
  ret i32 %call
 | 
						|
}
 | 
						|
 | 
						|
define i32 @myflsl() {
 | 
						|
; CHECK-LABEL: @myflsl(
 | 
						|
; CHECK-NEXT:    ret i32 6
 | 
						|
;
 | 
						|
  %patatino = call i32 @flsl(i64 42)
 | 
						|
  ret i32 %patatino
 | 
						|
}
 | 
						|
 | 
						|
define i32 @myflsll() {
 | 
						|
; CHECK-LABEL: @myflsll(
 | 
						|
; CHECK-NEXT:    ret i32 6
 | 
						|
;
 | 
						|
  %whatever = call i32 @flsll(i64 42)
 | 
						|
  ret i32 %whatever
 | 
						|
}
 | 
						|
 | 
						|
; Lower to llvm.ctlz() if the argument is not a constant
 | 
						|
 | 
						|
define i32 @flsnotconst(i64 %z) {
 | 
						|
; CHECK-LABEL: @flsnotconst(
 | 
						|
; CHECK-NEXT:    [[CTLZ:%.*]] = call i64 @llvm.ctlz.i64(i64 %z, i1 false), !range !0
 | 
						|
; CHECK-NEXT:    [[TMP1:%.*]] = trunc i64 [[CTLZ]] to i32
 | 
						|
; CHECK-NEXT:    [[TMP2:%.*]] = sub nsw i32 64, [[TMP1]]
 | 
						|
; CHECK-NEXT:    ret i32 [[TMP2]]
 | 
						|
;
 | 
						|
  %goo = call i32 @flsl(i64 %z)
 | 
						|
  ret i32 %goo
 | 
						|
}
 | 
						|
 | 
						|
; Make sure we lower fls(0) to 0 and not to `undef`.
 | 
						|
 | 
						|
define i32 @flszero() {
 | 
						|
; CHECK-LABEL: @flszero(
 | 
						|
; CHECK-NEXT:    ret i32 0
 | 
						|
;
 | 
						|
  %zero = call i32 @fls(i32 0)
 | 
						|
  ret i32 %zero
 | 
						|
}
 | 
						|
 | 
						|
declare i32 @fls(i32)
 | 
						|
declare i32 @flsl(i64)
 | 
						|
declare i32 @flsll(i64)
 |