; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; RUN: opt < %s -instcombine -S | FileCheck %s ; If we have some pattern that leaves only some low bits set, and then performs ; left-shift of those bits, we can combine those two shifts into a shift+mask. ; There are many variants to this pattern: ; c) (trunc ((x & (-1 >> maskNbits)))) << shiftNbits ; simplify to: ; (trunc(x)) << shiftNbits ; Simple tests. declare void @use32(i32) declare void @use64(i64) define i32 @t0_basic(i64 %x, i32 %nbits) { ; CHECK-LABEL: @t0_basic( ; CHECK-NEXT: [[T0:%.*]] = zext i32 [[NBITS:%.*]] to i64 ; CHECK-NEXT: [[T1:%.*]] = lshr i64 -1, [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add i32 [[NBITS]], -32 ; CHECK-NEXT: [[T3:%.*]] = and i64 [[T1]], [[X:%.*]] ; CHECK-NEXT: call void @use64(i64 [[T0]]) ; CHECK-NEXT: call void @use64(i64 [[T1]]) ; CHECK-NEXT: call void @use32(i32 [[T2]]) ; CHECK-NEXT: call void @use64(i64 [[T3]]) ; CHECK-NEXT: [[TMP1:%.*]] = trunc i64 [[X]] to i32 ; CHECK-NEXT: [[T5:%.*]] = shl i32 [[TMP1]], [[T2]] ; CHECK-NEXT: ret i32 [[T5]] ; %t0 = zext i32 %nbits to i64 %t1 = lshr i64 -1, %t0 %t2 = add i32 %nbits, -32 %t3 = and i64 %t1, %x call void @use64(i64 %t0) call void @use64(i64 %t1) call void @use32(i32 %t2) call void @use64(i64 %t3) %t4 = trunc i64 %t3 to i32 %t5 = shl i32 %t4, %t2 ret i32 %t5 } ; Vectors declare void @use8xi32(<8 x i32>) declare void @use8xi64(<8 x i64>) define <8 x i32> @t1_vec_splat(<8 x i64> %x, <8 x i32> %nbits) { ; CHECK-LABEL: @t1_vec_splat( ; CHECK-NEXT: [[T0:%.*]] = zext <8 x i32> [[NBITS:%.*]] to <8 x i64> ; CHECK-NEXT: [[T1:%.*]] = lshr <8 x i64> , [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add <8 x i32> [[NBITS]], ; CHECK-NEXT: [[T3:%.*]] = and <8 x i64> [[T1]], [[X:%.*]] ; CHECK-NEXT: call void @use8xi64(<8 x i64> [[T0]]) ; CHECK-NEXT: call void @use8xi64(<8 x i64> [[T1]]) ; CHECK-NEXT: call void @use8xi32(<8 x i32> [[T2]]) ; CHECK-NEXT: call void @use8xi64(<8 x i64> [[T3]]) ; CHECK-NEXT: [[TMP1:%.*]] = trunc <8 x i64> [[X]] to <8 x i32> ; CHECK-NEXT: [[T5:%.*]] = shl <8 x i32> [[TMP1]], [[T2]] ; CHECK-NEXT: ret <8 x i32> [[T5]] ; %t0 = zext <8 x i32> %nbits to <8 x i64> %t1 = lshr <8 x i64> , %t0 %t2 = add <8 x i32> %nbits, %t3 = and <8 x i64> %t1, %x call void @use8xi64(<8 x i64> %t0) call void @use8xi64(<8 x i64> %t1) call void @use8xi32(<8 x i32> %t2) call void @use8xi64(<8 x i64> %t3) %t4 = trunc <8 x i64> %t3 to <8 x i32> %t5 = shl <8 x i32> %t4, %t2 ret <8 x i32> %t5 } define <8 x i32> @t2_vec_splat_undef(<8 x i64> %x, <8 x i32> %nbits) { ; CHECK-LABEL: @t2_vec_splat_undef( ; CHECK-NEXT: [[T0:%.*]] = zext <8 x i32> [[NBITS:%.*]] to <8 x i64> ; CHECK-NEXT: [[T1:%.*]] = lshr <8 x i64> , [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add <8 x i32> [[NBITS]], ; CHECK-NEXT: [[T3:%.*]] = and <8 x i64> [[T1]], [[X:%.*]] ; CHECK-NEXT: call void @use8xi64(<8 x i64> [[T0]]) ; CHECK-NEXT: call void @use8xi64(<8 x i64> [[T1]]) ; CHECK-NEXT: call void @use8xi32(<8 x i32> [[T2]]) ; CHECK-NEXT: call void @use8xi64(<8 x i64> [[T3]]) ; CHECK-NEXT: [[TMP1:%.*]] = trunc <8 x i64> [[X]] to <8 x i32> ; CHECK-NEXT: [[T5:%.*]] = shl <8 x i32> [[TMP1]], [[T2]] ; CHECK-NEXT: ret <8 x i32> [[T5]] ; %t0 = zext <8 x i32> %nbits to <8 x i64> %t1 = lshr <8 x i64> , %t0 %t2 = add <8 x i32> %nbits, %t3 = and <8 x i64> %t1, %x call void @use8xi64(<8 x i64> %t0) call void @use8xi64(<8 x i64> %t1) call void @use8xi32(<8 x i32> %t2) call void @use8xi64(<8 x i64> %t3) %t4 = trunc <8 x i64> %t3 to <8 x i32> %t5 = shl <8 x i32> %t4, %t2 ret <8 x i32> %t5 } define <8 x i32> @t3_vec_nonsplat(<8 x i64> %x, <8 x i32> %nbits) { ; CHECK-LABEL: @t3_vec_nonsplat( ; CHECK-NEXT: [[T0:%.*]] = zext <8 x i32> [[NBITS:%.*]] to <8 x i64> ; CHECK-NEXT: [[T1:%.*]] = lshr <8 x i64> , [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add <8 x i32> [[NBITS]], ; CHECK-NEXT: [[T3:%.*]] = and <8 x i64> [[T1]], [[X:%.*]] ; CHECK-NEXT: call void @use8xi64(<8 x i64> [[T0]]) ; CHECK-NEXT: call void @use8xi64(<8 x i64> [[T1]]) ; CHECK-NEXT: call void @use8xi32(<8 x i32> [[T2]]) ; CHECK-NEXT: call void @use8xi64(<8 x i64> [[T3]]) ; CHECK-NEXT: [[TMP1:%.*]] = trunc <8 x i64> [[X]] to <8 x i32> ; CHECK-NEXT: [[T5:%.*]] = shl <8 x i32> [[TMP1]], [[T2]] ; CHECK-NEXT: ret <8 x i32> [[T5]] ; %t0 = zext <8 x i32> %nbits to <8 x i64> %t1 = lshr <8 x i64> , %t0 %t2 = add <8 x i32> %nbits, %t3 = and <8 x i64> %t1, %x call void @use8xi64(<8 x i64> %t0) call void @use8xi64(<8 x i64> %t1) call void @use8xi32(<8 x i32> %t2) call void @use8xi64(<8 x i64> %t3) %t4 = trunc <8 x i64> %t3 to <8 x i32> %t5 = shl <8 x i32> %t4, %t2 ret <8 x i32> %t5 } ; Extra uses. define i32 @n4_extrause(i64 %x, i32 %nbits) { ; CHECK-LABEL: @n4_extrause( ; CHECK-NEXT: [[T0:%.*]] = zext i32 [[NBITS:%.*]] to i64 ; CHECK-NEXT: [[T1:%.*]] = lshr i64 -1, [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add i32 [[NBITS]], -32 ; CHECK-NEXT: [[T3:%.*]] = and i64 [[T1]], [[X:%.*]] ; CHECK-NEXT: call void @use64(i64 [[T0]]) ; CHECK-NEXT: call void @use64(i64 [[T1]]) ; CHECK-NEXT: call void @use32(i32 [[T2]]) ; CHECK-NEXT: call void @use64(i64 [[T3]]) ; CHECK-NEXT: [[T4:%.*]] = trunc i64 [[T3]] to i32 ; CHECK-NEXT: call void @use32(i32 [[T4]]) ; CHECK-NEXT: [[T5:%.*]] = shl i32 [[T4]], [[T2]] ; CHECK-NEXT: ret i32 [[T5]] ; %t0 = zext i32 %nbits to i64 %t1 = lshr i64 -1, %t0 %t2 = add i32 %nbits, -32 %t3 = and i64 %t1, %x call void @use64(i64 %t0) call void @use64(i64 %t1) call void @use32(i32 %t2) call void @use64(i64 %t3) %t4 = trunc i64 %t3 to i32 call void @use32(i32 %t4) %t5 = shl i32 %t4, %t2 ret i32 %t5 }