fls.ll
1.13 KB
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; 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)