1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py 2; RUN: opt -mcpu=core-avx2 < %s -O3 -S | FileCheck --check-prefix=ALL %s 3; RUN: opt -mcpu=core-avx2 < %s -passes="default<O3>" -S | FileCheck --check-prefix=ALL %s 4 5; Not only should we be able to make the loop countable, 6; %whatever.next recurrence should be rewritten, making loop dead. 7 8target triple = "x86_64--" 9target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" 10 11define i32 @cttz(i32 %n, ptr %p1) { 12; ALL-LABEL: @cttz( 13; ALL-NEXT: entry: 14; ALL-NEXT: [[TMP0:%.*]] = shl i32 [[N:%.*]], 1 15; ALL-NEXT: [[TMP1:%.*]] = tail call range(i32 1, 33) i32 @llvm.cttz.i32(i32 [[TMP0]], i1 false) 16; ALL-NEXT: [[TMP2:%.*]] = sub nuw nsw i32 32, [[TMP1]] 17; ALL-NEXT: [[TMP3:%.*]] = sub nuw nsw i32 75, [[TMP1]] 18; ALL-NEXT: store i32 [[TMP3]], ptr [[P1:%.*]], align 4 19; ALL-NEXT: ret i32 [[TMP2]] 20; 21entry: 22 br label %while.cond 23 24while.cond: ; preds = %while.cond, %entry 25 %n.addr.0 = phi i32 [ %n, %entry ], [ %shl, %while.cond ] 26 %whatever = phi i32 [ 42, %entry ], [ %whatever.next, %while.cond ] 27 %i.0 = phi i32 [ 0, %entry ], [ %inc, %while.cond ] 28 %shl = shl i32 %n.addr.0, 1 29 %tobool = icmp eq i32 %shl, 0 30 %inc = add nsw i32 %i.0, 1 31 %whatever.next = add i32 %whatever, 1 32 br i1 %tobool, label %while.end, label %while.cond 33 34while.end: ; preds = %while.cond 35 store i32 %whatever.next, ptr %p1 36 ret i32 %i.0 37} 38