llvm-project/llvm/test/Transforms/InstCombine/select-ctlz-to-cttz.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -instcombine -S < %s | FileCheck %s


declare i32 @llvm.cttz.i32(i32, i1 immarg)
declare i32 @llvm.ctlz.i32(i32, i1 immarg)
declare i64 @llvm.cttz.i64(i64, i1 immarg)
declare i64 @llvm.ctlz.i64(i64, i1 immarg)

declare <2 x i32> @llvm.ctlz.v2i32(<2 x i32>, i1)
declare <2 x i32> @llvm.cttz.v2i32(<2 x i32>, i1)


declare void @use(i32)
declare void @use2(i1)

define i32 @select_clz_to_ctz(i32 %a) {
; CHECK-LABEL: @select_clz_to_ctz(
; CHECK-NEXT:    [[COND:%.*]] = call i32 @llvm.cttz.i32(i32 [[A:%.*]], i1 true), !range !0
; CHECK-NEXT:    ret i32 [[COND]]
;
  %sub = sub i32 0, %a
  %and = and i32 %sub, %a
  %lz = tail call i32 @llvm.ctlz.i32(i32 %and, i1 true)
  %tobool = icmp eq i32 %a, 0
  %sub1 = xor i32 %lz, 31
  %cond = select i1 %tobool, i32 %lz, i32 %sub1
  ret i32 %cond
}

define i32 @select_clz_to_ctz_preserve_flag(i32 %a) {
; CHECK-LABEL: @select_clz_to_ctz_preserve_flag(
; CHECK-NEXT:    [[COND:%.*]] = call i32 @llvm.cttz.i32(i32 [[A:%.*]], i1 false), !range !0
; CHECK-NEXT:    ret i32 [[COND]]
;
  %sub = sub i32 0, %a
  %and = and i32 %sub, %a
  %lz = tail call i32 @llvm.ctlz.i32(i32 %and, i1 false)
  %tobool = icmp eq i32 %a, 0
  %sub1 = xor i32 %lz, 31
  %cond = select i1 %tobool, i32 %lz, i32 %sub1
  ret i32 %cond
}

define <2 x i32> @select_clz_to_ctz_vec(<2 x i32> %a) {
; CHECK-LABEL: @select_clz_to_ctz_vec(
; CHECK-NEXT:    [[COND:%.*]] = call <2 x i32> @llvm.cttz.v2i32(<2 x i32> [[A:%.*]], i1 true)
; CHECK-NEXT:    ret <2 x i32> [[COND]]
;
  %sub = sub <2 x i32> zeroinitializer, %a
  %and = and <2 x i32> %sub, %a
  %lz = tail call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> %and, i1 true)
  %tobool = icmp eq <2 x i32> %a, zeroinitializer
  %sub1 = xor <2 x i32> %lz, <i32 31, i32 31>
  %cond = select <2 x i1> %tobool, <2 x i32> %lz, <2 x i32> %sub1
  ret <2 x i32> %cond
}

define i32 @select_clz_to_ctz_extra_use(i32 %a) {
; CHECK-LABEL: @select_clz_to_ctz_extra_use(
; CHECK-NEXT:    [[SUB:%.*]] = sub i32 0, [[A:%.*]]
; CHECK-NEXT:    [[AND:%.*]] = and i32 [[SUB]], [[A]]
; CHECK-NEXT:    [[LZ:%.*]] = tail call i32 @llvm.ctlz.i32(i32 [[AND]], i1 true), !range !0
; CHECK-NEXT:    [[SUB1:%.*]] = xor i32 [[LZ]], 31
; CHECK-NEXT:    call void @use(i32 [[SUB1]])
; CHECK-NEXT:    [[COND:%.*]] = call i32 @llvm.cttz.i32(i32 [[A]], i1 true), !range !0
; CHECK-NEXT:    ret i32 [[COND]]
;
  %sub = sub i32 0, %a
  %and = and i32 %sub, %a
  %lz = tail call i32 @llvm.ctlz.i32(i32 %and, i1 true)
  %tobool = icmp eq i32 %a, 0
  %sub1 = xor i32 %lz, 31
  call void @use(i32 %sub1)
  %cond = select i1 %tobool, i32 %lz, i32 %sub1
  ret i32 %cond
}

define i32 @select_clz_to_ctz_and_commuted(i32 %a) {
; CHECK-LABEL: @select_clz_to_ctz_and_commuted(
; CHECK-NEXT:    [[COND:%.*]] = call i32 @llvm.cttz.i32(i32 [[A:%.*]], i1 true), !range !0
; CHECK-NEXT:    ret i32 [[COND]]
;
  %sub = sub i32 0, %a
  %and = and i32 %a, %sub
  %lz = tail call i32 @llvm.ctlz.i32(i32 %and, i1 true)
  %tobool = icmp eq i32 %a, 0
  %sub1 = xor i32 %lz, 31
  %cond = select i1 %tobool, i32 %lz, i32 %sub1
  ret i32 %cond
}

define i32 @select_clz_to_ctz_icmp_ne(i32 %a) {
; CHECK-LABEL: @select_clz_to_ctz_icmp_ne(
; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp ne i32 [[A:%.*]], 0
; CHECK-NEXT:    call void @use2(i1 [[TOBOOL]])
; CHECK-NEXT:    [[COND:%.*]] = call i32 @llvm.cttz.i32(i32 [[A]], i1 true), !range !0
; CHECK-NEXT:    ret i32 [[COND]]
;
  %sub = sub i32 0, %a
  %and = and i32 %sub, %a
  %lz = tail call i32 @llvm.ctlz.i32(i32 %and, i1 true)
  %tobool = icmp ne i32 %a, 0
  call void @use2(i1 %tobool)
  %sub1 = xor i32 %lz, 31
  %cond = select i1 %tobool, i32 %sub1, i32 %lz
  ret i32 %cond
}

define i64 @select_clz_to_ctz_i64(i64 %a) {
; CHECK-LABEL: @select_clz_to_ctz_i64(
; CHECK-NEXT:    [[COND:%.*]] = call i64 @llvm.cttz.i64(i64 [[A:%.*]], i1 true), !range !1
; CHECK-NEXT:    ret i64 [[COND]]
;
  %sub = sub i64 0, %a
  %and = and i64 %sub, %a
  %lz = tail call i64 @llvm.ctlz.i64(i64 %and, i1 true)
  %tobool = icmp eq i64 %a, 0
  %sub1 = xor i64 %lz, 63
  %cond = select i1 %tobool, i64 %lz, i64 %sub1
  ret i64 %cond
}

; Negative tests

define i32 @select_clz_to_ctz_wrong_sub(i32 %a) {
; CHECK-LABEL: @select_clz_to_ctz_wrong_sub(
; CHECK-NEXT:    [[SUB:%.*]] = sub i32 1, [[A:%.*]]
; CHECK-NEXT:    [[AND:%.*]] = and i32 [[SUB]], [[A]]
; CHECK-NEXT:    [[LZ:%.*]] = tail call i32 @llvm.ctlz.i32(i32 [[AND]], i1 true), !range !0
; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i32 [[A]], 0
; CHECK-NEXT:    [[SUB1:%.*]] = xor i32 [[LZ]], 31
; CHECK-NEXT:    [[COND:%.*]] = select i1 [[TOBOOL]], i32 [[LZ]], i32 [[SUB1]]
; CHECK-NEXT:    ret i32 [[COND]]
;
  %sub = sub i32 1, %a
  %and = and i32 %sub, %a
  %lz = tail call i32 @llvm.ctlz.i32(i32 %and, i1 true)
  %tobool = icmp eq i32 %a, 0
  %sub1 = xor i32 %lz, 31
  %cond = select i1 %tobool, i32 %lz, i32 %sub1
  ret i32 %cond
}

define i64 @select_clz_to_ctz_i64_wrong_xor(i64 %a) {
; CHECK-LABEL: @select_clz_to_ctz_i64_wrong_xor(
; CHECK-NEXT:    [[SUB:%.*]] = sub i64 0, [[A:%.*]]
; CHECK-NEXT:    [[AND:%.*]] = and i64 [[SUB]], [[A]]
; CHECK-NEXT:    [[LZ:%.*]] = tail call i64 @llvm.ctlz.i64(i64 [[AND]], i1 true), !range !1
; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i64 [[A]], 0
; CHECK-NEXT:    [[SUB11:%.*]] = or i64 [[LZ]], 64
; CHECK-NEXT:    [[COND:%.*]] = select i1 [[TOBOOL]], i64 [[LZ]], i64 [[SUB11]]
; CHECK-NEXT:    ret i64 [[COND]]
;
  %sub = sub i64 0, %a
  %and = and i64 %sub, %a
  %lz = tail call i64 @llvm.ctlz.i64(i64 %and, i1 true)
  %tobool = icmp eq i64 %a, 0
  %sub1 = xor i64 %lz, 64
  %cond = select i1 %tobool, i64 %lz, i64 %sub1
  ret i64 %cond
}

define i64 @select_clz_to_ctz_i64_wrong_icmp_cst(i64 %a) {
; CHECK-LABEL: @select_clz_to_ctz_i64_wrong_icmp_cst(
; CHECK-NEXT:    [[SUB:%.*]] = sub i64 0, [[A:%.*]]
; CHECK-NEXT:    [[AND:%.*]] = and i64 [[SUB]], [[A]]
; CHECK-NEXT:    [[LZ:%.*]] = tail call i64 @llvm.ctlz.i64(i64 [[AND]], i1 true), !range !1
; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i64 [[A]], 1
; CHECK-NEXT:    [[SUB1:%.*]] = xor i64 [[LZ]], 63
; CHECK-NEXT:    [[COND:%.*]] = select i1 [[TOBOOL]], i64 [[LZ]], i64 [[SUB1]]
; CHECK-NEXT:    ret i64 [[COND]]
;
  %sub = sub i64 0, %a
  %and = and i64 %sub, %a
  %lz = tail call i64 @llvm.ctlz.i64(i64 %and, i1 true)
  %tobool = icmp eq i64 %a, 1
  %sub1 = xor i64 %lz, 63
  %cond = select i1 %tobool, i64 %lz, i64 %sub1
  ret i64 %cond
}

define i64 @select_clz_to_ctz_i64_wrong_icmp_pred(i64 %a) {
; CHECK-LABEL: @select_clz_to_ctz_i64_wrong_icmp_pred(
; CHECK-NEXT:    [[SUB:%.*]] = sub i64 0, [[A:%.*]]
; CHECK-NEXT:    [[AND:%.*]] = and i64 [[SUB]], [[A]]
; CHECK-NEXT:    [[LZ:%.*]] = tail call i64 @llvm.ctlz.i64(i64 [[AND]], i1 true), !range !1
; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp slt i64 [[A]], 0
; CHECK-NEXT:    [[SUB1:%.*]] = xor i64 [[LZ]], 63
; CHECK-NEXT:    [[COND:%.*]] = select i1 [[TOBOOL]], i64 [[LZ]], i64 [[SUB1]]
; CHECK-NEXT:    ret i64 [[COND]]
;
  %sub = sub i64 0, %a
  %and = and i64 %sub, %a
  %lz = tail call i64 @llvm.ctlz.i64(i64 %and, i1 true)
  %tobool = icmp slt i64 %a, 0
  %sub1 = xor i64 %lz, 63
  %cond = select i1 %tobool, i64 %lz, i64 %sub1
  ret i64 %cond
}

define <2 x i32> @select_clz_to_ctz_vec_with_undef(<2 x i32> %a) {
; CHECK-LABEL: @select_clz_to_ctz_vec_with_undef(
; CHECK-NEXT:    [[SUB:%.*]] = sub <2 x i32> zeroinitializer, [[A:%.*]]
; CHECK-NEXT:    [[AND:%.*]] = and <2 x i32> [[SUB]], [[A]]
; CHECK-NEXT:    [[LZ:%.*]] = tail call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> [[AND]], i1 true)
; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq <2 x i32> [[A]], zeroinitializer
; CHECK-NEXT:    [[SUB1:%.*]] = xor <2 x i32> [[LZ]], <i32 31, i32 undef>
; CHECK-NEXT:    [[COND:%.*]] = select <2 x i1> [[TOBOOL]], <2 x i32> [[LZ]], <2 x i32> [[SUB1]]
; CHECK-NEXT:    ret <2 x i32> [[COND]]
;
  %sub = sub <2 x i32> zeroinitializer, %a
  %and = and <2 x i32> %sub, %a
  %lz = tail call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> %and, i1 true)
  %tobool = icmp eq <2 x i32> %a, zeroinitializer
  %sub1 = xor <2 x i32> %lz, <i32 31, i32 undef>
  %cond = select <2 x i1> %tobool, <2 x i32> %lz, <2 x i32> %sub1
  ret <2 x i32> %cond
}