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; RUN: opt -loop-idiom -mtriple=x86_64 -mcpu=core-avx2 < %s -S | FileCheck --check-prefix=ALL %s
; RUN: opt -loop-idiom -mtriple=x86_64 -mcpu=corei7 < %s -S | FileCheck --check-prefix=ALL %s
; Recognize CTTZ builtin pattern.
; Here it will replace the loop -
; assume builtin is always profitable.
;
; int cttz_zero_check(int n)
; {
; int i = 0;
; while(n) {
; n <<= 1;
; i++;
; }
; return i;
; }
;
; ALL-LABEL: @cttz_zero_check
; ALL: %0 = call i32 @llvm.cttz.i32(i32 %n, i1 true)
; ALL-NEXT: %1 = sub i32 32, %0
;
; Function Attrs: norecurse nounwind readnone uwtable
define i32 @cttz_zero_check(i32 %n) {
entry:
%tobool4 = icmp eq i32 %n, 0
br i1 %tobool4, label %while.end, label %while.body.preheader
while.body.preheader: ; preds = %entry
br label %while.body
while.body: ; preds = %while.body.preheader, %while.body
%i.06 = phi i32 [ %inc, %while.body ], [ 0, %while.body.preheader ]
%n.addr.05 = phi i32 [ %shl, %while.body ], [ %n, %while.body.preheader ]
%shl = shl i32 %n.addr.05, 1
%inc = add nsw i32 %i.06, 1
%tobool = icmp eq i32 %shl, 0
br i1 %tobool, label %while.end.loopexit, label %while.body
while.end.loopexit: ; preds = %while.body
br label %while.end
while.end: ; preds = %while.end.loopexit, %entry
%i.0.lcssa = phi i32 [ 0, %entry ], [ %inc, %while.end.loopexit ]
ret i32 %i.0.lcssa
}
; Recognize CTTZ builtin pattern.
; Here it will replace the loop -
; assume builtin is always profitable.
;
; int cttz(int n)
; {
; int i = 0;
; while(n <<= 1) {
; i++;
; }
; return i;
; }
;
; ALL-LABEL: @cttz
; ALL: %0 = shl i32 %n, 1
; ALL-NEXT: %1 = call i32 @llvm.cttz.i32(i32 %0, i1 false)
; ALL-NEXT: %2 = sub i32 32, %1
; ALL-NEXT: %3 = add i32 %2, 1
;
; Function Attrs: norecurse nounwind readnone uwtable
define i32 @cttz(i32 %n) {
entry:
br label %while.cond
while.cond: ; preds = %while.cond, %entry
%n.addr.0 = phi i32 [ %n, %entry ], [ %shl, %while.cond ]
%i.0 = phi i32 [ 0, %entry ], [ %inc, %while.cond ]
%shl = shl i32 %n.addr.0, 1
%tobool = icmp eq i32 %shl, 0
%inc = add nsw i32 %i.0, 1
br i1 %tobool, label %while.end, label %while.cond
while.end: ; preds = %while.cond
ret i32 %i.0
}
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