224 lines
6.4 KiB
LLVM
224 lines
6.4 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -passes=instcombine -S | FileCheck %s
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; Iff we know that trunc only chops off the sign bits,
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; and not all of them, then we can bypass said trunc
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; for the purpose of sign extension.
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declare void @use8(i8)
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declare void @use4(i4)
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declare void @usevec(<2 x i8>)
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define i16 @t0(i8 %x) {
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; CHECK-LABEL: @t0(
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; CHECK-NEXT: [[A:%.*]] = ashr i8 [[X:%.*]], 5
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; CHECK-NEXT: call void @use8(i8 [[A]])
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; CHECK-NEXT: [[C:%.*]] = sext i8 [[A]] to i16
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; CHECK-NEXT: ret i16 [[C]]
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;
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%a = ashr i8 %x, 5
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call void @use8(i8 %a)
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%b = trunc i8 %a to i4
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%c = sext i4 %b to i16
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ret i16 %c
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}
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define i16 @t1(i8 %x) {
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; CHECK-LABEL: @t1(
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; CHECK-NEXT: [[A:%.*]] = ashr i8 [[X:%.*]], 4
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; CHECK-NEXT: call void @use8(i8 [[A]])
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; CHECK-NEXT: [[C:%.*]] = sext i8 [[A]] to i16
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; CHECK-NEXT: ret i16 [[C]]
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;
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%a = ashr i8 %x, 4
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call void @use8(i8 %a)
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%b = trunc i8 %a to i4
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%c = sext i4 %b to i16
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ret i16 %c
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}
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; Here we don't know that %a has any sign bits from %x left
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define i16 @n2(i8 %x) {
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; CHECK-LABEL: @n2(
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; CHECK-NEXT: [[A:%.*]] = ashr i8 [[X:%.*]], 3
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; CHECK-NEXT: call void @use8(i8 [[A]])
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; CHECK-NEXT: [[B:%.*]] = trunc i8 [[A]] to i4
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; CHECK-NEXT: [[C:%.*]] = sext i4 [[B]] to i16
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; CHECK-NEXT: ret i16 [[C]]
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;
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%a = ashr i8 %x, 3
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call void @use8(i8 %a)
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%b = trunc i8 %a to i4
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%c = sext i4 %b to i16
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ret i16 %c
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}
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define <2 x i16> @t3_vec(<2 x i8> %x) {
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; CHECK-LABEL: @t3_vec(
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; CHECK-NEXT: [[A:%.*]] = ashr <2 x i8> [[X:%.*]], <i8 4, i8 4>
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; CHECK-NEXT: call void @usevec(<2 x i8> [[A]])
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; CHECK-NEXT: [[C:%.*]] = sext <2 x i8> [[A]] to <2 x i16>
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; CHECK-NEXT: ret <2 x i16> [[C]]
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;
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%a = ashr <2 x i8> %x, <i8 4, i8 4>
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call void @usevec(<2 x i8> %a)
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%b = trunc <2 x i8> %a to <2 x i4>
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%c = sext <2 x i4> %b to <2 x i16>
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ret <2 x i16> %c
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}
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define <2 x i16> @t4_vec_nonsplat(<2 x i8> %x) {
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; CHECK-LABEL: @t4_vec_nonsplat(
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; CHECK-NEXT: [[A:%.*]] = ashr <2 x i8> [[X:%.*]], <i8 4, i8 3>
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; CHECK-NEXT: call void @usevec(<2 x i8> [[A]])
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; CHECK-NEXT: [[B:%.*]] = trunc <2 x i8> [[A]] to <2 x i4>
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; CHECK-NEXT: [[C:%.*]] = sext <2 x i4> [[B]] to <2 x i16>
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; CHECK-NEXT: ret <2 x i16> [[C]]
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;
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%a = ashr <2 x i8> %x, <i8 4, i8 3>
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call void @usevec(<2 x i8> %a)
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%b = trunc <2 x i8> %a to <2 x i4>
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%c = sext <2 x i4> %b to <2 x i16>
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ret <2 x i16> %c
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}
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define i16 @t5_extrause(i8 %x) {
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; CHECK-LABEL: @t5_extrause(
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; CHECK-NEXT: [[A:%.*]] = ashr i8 [[X:%.*]], 5
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; CHECK-NEXT: call void @use8(i8 [[A]])
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; CHECK-NEXT: [[B:%.*]] = trunc i8 [[A]] to i4
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; CHECK-NEXT: call void @use4(i4 [[B]])
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; CHECK-NEXT: [[C:%.*]] = sext i8 [[A]] to i16
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; CHECK-NEXT: ret i16 [[C]]
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;
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%a = ashr i8 %x, 5
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call void @use8(i8 %a)
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%b = trunc i8 %a to i4
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call void @use4(i4 %b)
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%c = sext i4 %b to i16
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ret i16 %c
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}
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define i64 @narrow_source_matching_signbits(i32 %x) {
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; CHECK-LABEL: @narrow_source_matching_signbits(
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; CHECK-NEXT: [[M:%.*]] = and i32 [[X:%.*]], 7
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; CHECK-NEXT: [[A:%.*]] = shl nsw i32 -1, [[M]]
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; CHECK-NEXT: [[C:%.*]] = sext i32 [[A]] to i64
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; CHECK-NEXT: ret i64 [[C]]
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;
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%m = and i32 %x, 7
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%a = shl nsw i32 -1, %m
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%b = trunc i32 %a to i8
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%c = sext i8 %b to i64
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ret i64 %c
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}
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; negative test - not enough sign-bits
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define i64 @narrow_source_not_matching_signbits(i32 %x) {
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; CHECK-LABEL: @narrow_source_not_matching_signbits(
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; CHECK-NEXT: [[M:%.*]] = and i32 [[X:%.*]], 8
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; CHECK-NEXT: [[A:%.*]] = shl nsw i32 -1, [[M]]
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; CHECK-NEXT: [[B:%.*]] = trunc i32 [[A]] to i8
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; CHECK-NEXT: [[C:%.*]] = sext i8 [[B]] to i64
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; CHECK-NEXT: ret i64 [[C]]
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;
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%m = and i32 %x, 8
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%a = shl nsw i32 -1, %m
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%b = trunc i32 %a to i8
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%c = sext i8 %b to i64
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ret i64 %c
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}
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define i24 @wide_source_matching_signbits(i32 %x) {
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; CHECK-LABEL: @wide_source_matching_signbits(
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; CHECK-NEXT: [[M:%.*]] = and i32 [[X:%.*]], 7
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; CHECK-NEXT: [[A:%.*]] = shl nsw i32 -1, [[M]]
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; CHECK-NEXT: [[C:%.*]] = trunc i32 [[A]] to i24
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; CHECK-NEXT: ret i24 [[C]]
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;
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%m = and i32 %x, 7
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%a = shl nsw i32 -1, %m
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%b = trunc i32 %a to i8
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%c = sext i8 %b to i24
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ret i24 %c
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}
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; negative test - not enough sign-bits
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define i24 @wide_source_not_matching_signbits(i32 %x) {
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; CHECK-LABEL: @wide_source_not_matching_signbits(
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; CHECK-NEXT: [[M2:%.*]] = and i32 [[X:%.*]], 8
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; CHECK-NEXT: [[A:%.*]] = shl nsw i32 -1, [[M2]]
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; CHECK-NEXT: [[B:%.*]] = trunc i32 [[A]] to i8
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; CHECK-NEXT: [[C:%.*]] = sext i8 [[B]] to i24
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; CHECK-NEXT: ret i24 [[C]]
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;
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%m2 = and i32 %x, 8
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%a = shl nsw i32 -1, %m2
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%b = trunc i32 %a to i8
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%c = sext i8 %b to i24
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ret i24 %c
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}
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define i32 @same_source_matching_signbits(i32 %x) {
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; CHECK-LABEL: @same_source_matching_signbits(
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; CHECK-NEXT: [[M:%.*]] = and i32 [[X:%.*]], 7
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; CHECK-NEXT: [[A:%.*]] = shl nsw i32 -1, [[M]]
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; CHECK-NEXT: ret i32 [[A]]
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;
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%m = and i32 %x, 7
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%a = shl nsw i32 -1, %m
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%b = trunc i32 %a to i8
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%c = sext i8 %b to i32
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ret i32 %c
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}
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; negative test - not enough sign-bits
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define i32 @same_source_not_matching_signbits(i32 %x) {
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; CHECK-LABEL: @same_source_not_matching_signbits(
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; CHECK-NEXT: [[M2:%.*]] = and i32 [[X:%.*]], 8
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; CHECK-NEXT: [[TMP1:%.*]] = shl i32 -16777216, [[M2]]
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; CHECK-NEXT: [[C:%.*]] = ashr exact i32 [[TMP1]], 24
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; CHECK-NEXT: ret i32 [[C]]
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;
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%m2 = and i32 %x, 8
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%a = shl nsw i32 -1, %m2
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%b = trunc i32 %a to i8
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%c = sext i8 %b to i32
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ret i32 %c
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}
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define i32 @same_source_matching_signbits_extra_use(i32 %x) {
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; CHECK-LABEL: @same_source_matching_signbits_extra_use(
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; CHECK-NEXT: [[M:%.*]] = and i32 [[X:%.*]], 7
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; CHECK-NEXT: [[A:%.*]] = shl nsw i32 -1, [[M]]
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; CHECK-NEXT: [[B:%.*]] = trunc i32 [[A]] to i8
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; CHECK-NEXT: call void @use8(i8 [[B]])
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; CHECK-NEXT: ret i32 [[A]]
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;
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%m = and i32 %x, 7
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%a = shl nsw i32 -1, %m
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%b = trunc i32 %a to i8
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call void @use8(i8 %b)
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%c = sext i8 %b to i32
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ret i32 %c
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}
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define i32 @same_source_not_matching_signbits_extra_use(i32 %x) {
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; CHECK-LABEL: @same_source_not_matching_signbits_extra_use(
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; CHECK-NEXT: [[M2:%.*]] = and i32 [[X:%.*]], 8
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; CHECK-NEXT: [[A:%.*]] = shl nsw i32 -1, [[M2]]
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; CHECK-NEXT: [[B:%.*]] = trunc i32 [[A]] to i8
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; CHECK-NEXT: call void @use8(i8 [[B]])
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; CHECK-NEXT: [[C:%.*]] = sext i8 [[B]] to i32
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; CHECK-NEXT: ret i32 [[C]]
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;
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%m2 = and i32 %x, 8
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%a = shl nsw i32 -1, %m2
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%b = trunc i32 %a to i8
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call void @use8(i8 %b)
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%c = sext i8 %b to i32
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ret i32 %c
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}
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