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1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py2; RUN: opt -passes=instcombine -S < %s | FileCheck %s3 4; If we only want bits that already match the signbit then we don't need to shift.5 6define i32 @srem2_ashr_mask(i32 %a0) {7; CHECK-LABEL: @srem2_ashr_mask(8; CHECK-NEXT: [[SREM:%.*]] = srem i32 [[A0:%.*]], 29; CHECK-NEXT: [[MASK:%.*]] = and i32 [[SREM]], 210; CHECK-NEXT: ret i32 [[MASK]]11;12 %srem = srem i32 %a0, 2 ; result = (1,0,-1) num signbits = 3113 %ashr = ashr i32 %srem, 3114 %mask = and i32 %ashr, 215 ret i32 %mask16}17 18; Negative test - mask demands non-signbit from shift source19define i32 @srem8_ashr_mask(i32 %a0) {20; CHECK-LABEL: @srem8_ashr_mask(21; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[A0:%.*]], -214748364122; CHECK-NEXT: [[ISNEG:%.*]] = icmp ugt i32 [[TMP1]], -214748364823; CHECK-NEXT: [[MASK:%.*]] = select i1 [[ISNEG]], i32 2, i32 024; CHECK-NEXT: ret i32 [[MASK]]25;26 %srem = srem i32 %a0, 827 %ashr = ashr i32 %srem, 3128 %mask = and i32 %ashr, 229 ret i32 %mask30}31 32define <2 x i32> @srem2_ashr_mask_vector(<2 x i32> %a0) {33; CHECK-LABEL: @srem2_ashr_mask_vector(34; CHECK-NEXT: [[SREM:%.*]] = srem <2 x i32> [[A0:%.*]], splat (i32 2)35; CHECK-NEXT: [[MASK:%.*]] = and <2 x i32> [[SREM]], splat (i32 2)36; CHECK-NEXT: ret <2 x i32> [[MASK]]37;38 %srem = srem <2 x i32> %a0, <i32 2, i32 2>39 %ashr = ashr <2 x i32> %srem, <i32 31, i32 31>40 %mask = and <2 x i32> %ashr, <i32 2, i32 2>41 ret <2 x i32> %mask42}43 44define <2 x i32> @srem2_ashr_mask_vector_nonconstant(<2 x i32> %a0, <2 x i32> %a1) {45; CHECK-LABEL: @srem2_ashr_mask_vector_nonconstant(46; CHECK-NEXT: [[SREM:%.*]] = srem <2 x i32> [[A0:%.*]], splat (i32 2)47; CHECK-NEXT: [[MASK:%.*]] = and <2 x i32> [[SREM]], splat (i32 2)48; CHECK-NEXT: ret <2 x i32> [[MASK]]49;50 %srem = srem <2 x i32> %a0, <i32 2, i32 2>51 %ashr = ashr <2 x i32> %srem, %a152 %mask = and <2 x i32> %ashr, <i32 2, i32 2>53 ret <2 x i32> %mask54}55 56 57; If it does not matter if we do ashr or lshr, then we canonicalize to lshr.58 59define i16 @ashr_can_be_lshr(i32 %a) {60; CHECK-LABEL: @ashr_can_be_lshr(61; CHECK-NEXT: [[ASHR:%.*]] = lshr exact i32 [[A:%.*]], 1662; CHECK-NEXT: [[TRUNC:%.*]] = trunc nuw i32 [[ASHR]] to i1663; CHECK-NEXT: ret i16 [[TRUNC]]64;65 %ashr = ashr exact i32 %a, 1666 %trunc = trunc nsw i32 %ashr to i1667 ret i16 %trunc68}69 70; Historically SimplifyDemandedUseBits skipped replacing ashr with lshr here71; due to known sign bits analysis indicating that %ashr had more than 33 sign72; bits. It does however seem weird not to always canonicalize to lshr when73; possible, and in this case rewriting into lshr would trigger further74; optimizations.75define i32 @ashr_can_be_lshr_2(i32 %a) {76; CHECK-LABEL: @ashr_can_be_lshr_2(77; CHECK-NEXT: [[TMP1:%.*]] = shl i32 [[A:%.*]], 278; CHECK-NEXT: [[TMP2:%.*]] = or i32 [[TMP1]], -6710886479; CHECK-NEXT: ret i32 [[TMP2]]80;81 %ext = zext i32 %a to i6482 %or = or i64 %ext, 427819008083 %shl = shl i64 %or, 3484 %ashr = ashr exact i64 %shl, 3285 %trunc = trunc nsw i64 %ashr to i3286 ret i32 %trunc87}88