[llvm] 0ea4648 - [NFC][InstCombine] Add tests for sext-of-trunc-nuw-of-lshr (PR49543)
Roman Lebedev via llvm-commits
llvm-commits at lists.llvm.org
Tue Apr 20 14:33:43 PDT 2021
Author: Roman Lebedev
Date: 2021-04-21T00:31:46+03:00
New Revision: 0ea464824aa1fd28f86465d1671c7fd956cc514b
URL: https://github.com/llvm/llvm-project/commit/0ea464824aa1fd28f86465d1671c7fd956cc514b
DIFF: https://github.com/llvm/llvm-project/commit/0ea464824aa1fd28f86465d1671c7fd956cc514b.diff
LOG: [NFC][InstCombine] Add tests for sext-of-trunc-nuw-of-lshr (PR49543)
Added:
llvm/test/Transforms/InstCombine/lshr-trunc-sext-to-ashr-sext.ll
Modified:
Removed:
################################################################################
diff --git a/llvm/test/Transforms/InstCombine/lshr-trunc-sext-to-ashr-sext.ll b/llvm/test/Transforms/InstCombine/lshr-trunc-sext-to-ashr-sext.ll
new file mode 100644
index 000000000000..174bbcb088b1
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/lshr-trunc-sext-to-ashr-sext.ll
@@ -0,0 +1,178 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+; Iff trunc only chops off zero bits that were just shifted-in by the lshr,
+; but no other bits, then we can instead do signed shift, and signext it.
+; Note that we can replace trunc with trunc of new signed shift.
+
+declare void @use8(i8)
+declare void @use4(i4)
+declare void @usevec8(<2 x i8>)
+declare void @usevec4(<2 x i4>)
+
+define i16 @t0(i8 %x) {
+; CHECK-LABEL: @t0(
+; CHECK-NEXT: [[A:%.*]] = lshr i8 [[X:%.*]], 4
+; CHECK-NEXT: [[B:%.*]] = trunc i8 [[A]] to i4
+; CHECK-NEXT: [[C:%.*]] = sext i4 [[B]] to i16
+; CHECK-NEXT: ret i16 [[C]]
+;
+ %a = lshr i8 %x, 4
+ %b = trunc i8 %a to i4
+ %c = sext i4 %b to i16
+ ret i16 %c
+}
+
+define i16 @t1(i8 %x) {
+; CHECK-LABEL: @t1(
+; CHECK-NEXT: [[A:%.*]] = lshr i8 [[X:%.*]], 5
+; CHECK-NEXT: [[B:%.*]] = trunc i8 [[A]] to i3
+; CHECK-NEXT: [[C:%.*]] = sext i3 [[B]] to i16
+; CHECK-NEXT: ret i16 [[C]]
+;
+ %a = lshr i8 %x, 5
+ %b = trunc i8 %a to i3
+ %c = sext i3 %b to i16
+ ret i16 %c
+}
+
+define i16 @t2(i7 %x) {
+; CHECK-LABEL: @t2(
+; CHECK-NEXT: [[A:%.*]] = lshr i7 [[X:%.*]], 3
+; CHECK-NEXT: [[B:%.*]] = trunc i7 [[A]] to i4
+; CHECK-NEXT: [[C:%.*]] = sext i4 [[B]] to i16
+; CHECK-NEXT: ret i16 [[C]]
+;
+ %a = lshr i7 %x, 3
+ %b = trunc i7 %a to i4
+ %c = sext i4 %b to i16
+ ret i16 %c
+}
+
+define i16 @n3(i8 %x) {
+; CHECK-LABEL: @n3(
+; CHECK-NEXT: [[A:%.*]] = lshr i8 [[X:%.*]], 3
+; CHECK-NEXT: [[B:%.*]] = trunc i8 [[A]] to i4
+; CHECK-NEXT: [[C:%.*]] = sext i4 [[B]] to i16
+; CHECK-NEXT: ret i16 [[C]]
+;
+ %a = lshr i8 %x, 3
+ %b = trunc i8 %a to i4
+ %c = sext i4 %b to i16
+ ret i16 %c
+}
+
+define <2 x i16> @t4_vec_splat(<2 x i8> %x) {
+; CHECK-LABEL: @t4_vec_splat(
+; CHECK-NEXT: [[A:%.*]] = lshr <2 x i8> [[X:%.*]], <i8 4, i8 4>
+; CHECK-NEXT: [[B:%.*]] = trunc <2 x i8> [[A]] to <2 x i4>
+; CHECK-NEXT: [[C:%.*]] = sext <2 x i4> [[B]] to <2 x i16>
+; CHECK-NEXT: ret <2 x i16> [[C]]
+;
+ %a = lshr <2 x i8> %x, <i8 4, i8 4>
+ %b = trunc <2 x i8> %a to <2 x i4>
+ %c = sext <2 x i4> %b to <2 x i16>
+ ret <2 x i16> %c
+}
+
+define <2 x i16> @t5_vec_undef(<2 x i8> %x) {
+; CHECK-LABEL: @t5_vec_undef(
+; CHECK-NEXT: [[A:%.*]] = lshr <2 x i8> [[X:%.*]], <i8 4, i8 undef>
+; CHECK-NEXT: [[B:%.*]] = trunc <2 x i8> [[A]] to <2 x i4>
+; CHECK-NEXT: [[C:%.*]] = sext <2 x i4> [[B]] to <2 x i16>
+; CHECK-NEXT: ret <2 x i16> [[C]]
+;
+ %a = lshr <2 x i8> %x, <i8 4, i8 undef>
+ %b = trunc <2 x i8> %a to <2 x i4>
+ %c = sext <2 x i4> %b to <2 x i16>
+ ret <2 x i16> %c
+}
+
+define i16 @t6_extrause0(i8 %x) {
+; CHECK-LABEL: @t6_extrause0(
+; CHECK-NEXT: [[A:%.*]] = lshr i8 [[X:%.*]], 4
+; CHECK-NEXT: [[B:%.*]] = trunc i8 [[A]] to i4
+; CHECK-NEXT: call void @use4(i4 [[B]])
+; CHECK-NEXT: [[C:%.*]] = sext i4 [[B]] to i16
+; CHECK-NEXT: ret i16 [[C]]
+;
+ %a = lshr i8 %x, 4
+ %b = trunc i8 %a to i4 ; has extra use, but we can deal with that
+ call void @use4(i4 %b)
+ %c = sext i4 %b to i16
+ ret i16 %c
+}
+define <2 x i16> @t7_extrause0_vec_undef(<2 x i8> %x) {
+; CHECK-LABEL: @t7_extrause0_vec_undef(
+; CHECK-NEXT: [[A:%.*]] = lshr <2 x i8> [[X:%.*]], <i8 4, i8 undef>
+; CHECK-NEXT: [[B:%.*]] = trunc <2 x i8> [[A]] to <2 x i4>
+; CHECK-NEXT: call void @usevec4(<2 x i4> [[B]])
+; CHECK-NEXT: [[C:%.*]] = sext <2 x i4> [[B]] to <2 x i16>
+; CHECK-NEXT: ret <2 x i16> [[C]]
+;
+ %a = lshr <2 x i8> %x, <i8 4, i8 undef>
+ %b = trunc <2 x i8> %a to <2 x i4>
+ call void @usevec4(<2 x i4> %b)
+ %c = sext <2 x i4> %b to <2 x i16>
+ ret <2 x i16> %c
+}
+define i16 @t8_extrause1(i8 %x) {
+; CHECK-LABEL: @t8_extrause1(
+; CHECK-NEXT: [[A:%.*]] = lshr i8 [[X:%.*]], 4
+; CHECK-NEXT: call void @use8(i8 [[A]])
+; CHECK-NEXT: [[B:%.*]] = trunc i8 [[A]] to i4
+; CHECK-NEXT: [[C:%.*]] = sext i4 [[B]] to i16
+; CHECK-NEXT: ret i16 [[C]]
+;
+ %a = lshr i8 %x, 4 ; has extra use, but we can deal with that
+ call void @use8(i8 %a)
+ %b = trunc i8 %a to i4
+ %c = sext i4 %b to i16
+ ret i16 %c
+}
+define <2 x i16> @t9_extrause1_vec_undef(<2 x i8> %x) {
+; CHECK-LABEL: @t9_extrause1_vec_undef(
+; CHECK-NEXT: [[A:%.*]] = lshr <2 x i8> [[X:%.*]], <i8 4, i8 undef>
+; CHECK-NEXT: call void @usevec8(<2 x i8> [[A]])
+; CHECK-NEXT: [[B:%.*]] = trunc <2 x i8> [[A]] to <2 x i4>
+; CHECK-NEXT: [[C:%.*]] = sext <2 x i4> [[B]] to <2 x i16>
+; CHECK-NEXT: ret <2 x i16> [[C]]
+;
+ %a = lshr <2 x i8> %x, <i8 4, i8 undef>
+ call void @usevec8(<2 x i8> %a)
+ %b = trunc <2 x i8> %a to <2 x i4>
+ %c = sext <2 x i4> %b to <2 x i16>
+ ret <2 x i16> %c
+}
+define i16 @t10_extrause2(i8 %x) {
+; CHECK-LABEL: @t10_extrause2(
+; CHECK-NEXT: [[A:%.*]] = lshr i8 [[X:%.*]], 4
+; CHECK-NEXT: call void @use8(i8 [[A]])
+; CHECK-NEXT: [[B:%.*]] = trunc i8 [[A]] to i4
+; CHECK-NEXT: call void @use4(i4 [[B]])
+; CHECK-NEXT: [[C:%.*]] = sext i4 [[B]] to i16
+; CHECK-NEXT: ret i16 [[C]]
+;
+ %a = lshr i8 %x, 4 ; has extra use
+ call void @use8(i8 %a)
+ %b = trunc i8 %a to i4 ; has extra use
+ call void @use4(i4 %b)
+ %c = sext i4 %b to i16
+ ret i16 %c
+}
+define <2 x i16> @t11_extrause2_vec_undef(<2 x i8> %x) {
+; CHECK-LABEL: @t11_extrause2_vec_undef(
+; CHECK-NEXT: [[A:%.*]] = lshr <2 x i8> [[X:%.*]], <i8 4, i8 undef>
+; CHECK-NEXT: call void @usevec8(<2 x i8> [[A]])
+; CHECK-NEXT: [[B:%.*]] = trunc <2 x i8> [[A]] to <2 x i4>
+; CHECK-NEXT: call void @usevec4(<2 x i4> [[B]])
+; CHECK-NEXT: [[C:%.*]] = sext <2 x i4> [[B]] to <2 x i16>
+; CHECK-NEXT: ret <2 x i16> [[C]]
+;
+ %a = lshr <2 x i8> %x, <i8 4, i8 undef>
+ call void @usevec8(<2 x i8> %a)
+ %b = trunc <2 x i8> %a to <2 x i4>
+ call void @usevec4(<2 x i4> %b)
+ %c = sext <2 x i4> %b to <2 x i16>
+ ret <2 x i16> %c
+}
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