From: Roman Lebedev <lebedev.ri@gmail.com>
Date: Thu, 26 Sep 2019 20:49:30 +0000 (+0000)
Subject: [InstCombine][NFC] Add tests for shift-by-signext
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=0a14b051e5f900d5ce601cc45044e3401c4967dd;p=llvm

[InstCombine][NFC] Add tests for shift-by-signext

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@373013 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/test/Transforms/InstCombine/shift-by-signext.ll b/test/Transforms/InstCombine/shift-by-signext.ll
new file mode 100644
index 00000000000..dab37a4e7c0
--- /dev/null
+++ b/test/Transforms/InstCombine/shift-by-signext.ll
@@ -0,0 +1,105 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt %s -instcombine -S | FileCheck %s
+
+; If we have a shift by sign-extended value, we can replace sign-extension
+; with zero-extension.
+
+define i32 @t0_shl(i32 %x, i8 %shamt) {
+; CHECK-LABEL: @t0_shl(
+; CHECK-NEXT:    [[SHAMT_WIDE:%.*]] = sext i8 [[SHAMT:%.*]] to i32
+; CHECK-NEXT:    [[R:%.*]] = shl i32 [[X:%.*]], [[SHAMT_WIDE]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %shamt_wide = sext i8 %shamt to i32
+  %r = shl i32 %x, %shamt_wide
+  ret i32 %r
+}
+define i32 @t1_lshr(i32 %x, i8 %shamt) {
+; CHECK-LABEL: @t1_lshr(
+; CHECK-NEXT:    [[SHAMT_WIDE:%.*]] = sext i8 [[SHAMT:%.*]] to i32
+; CHECK-NEXT:    [[R:%.*]] = lshr i32 [[X:%.*]], [[SHAMT_WIDE]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %shamt_wide = sext i8 %shamt to i32
+  %r = lshr i32 %x, %shamt_wide
+  ret i32 %r
+}
+define i32 @t2_ashr(i32 %x, i8 %shamt) {
+; CHECK-LABEL: @t2_ashr(
+; CHECK-NEXT:    [[SHAMT_WIDE:%.*]] = sext i8 [[SHAMT:%.*]] to i32
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X:%.*]], [[SHAMT_WIDE]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %shamt_wide = sext i8 %shamt to i32
+  %r = ashr i32 %x, %shamt_wide
+  ret i32 %r
+}
+
+define <2 x i32> @t3_vec_shl(<2 x i32> %x, <2 x i8> %shamt) {
+; CHECK-LABEL: @t3_vec_shl(
+; CHECK-NEXT:    [[SHAMT_WIDE:%.*]] = sext <2 x i8> [[SHAMT:%.*]] to <2 x i32>
+; CHECK-NEXT:    [[R:%.*]] = shl <2 x i32> [[X:%.*]], [[SHAMT_WIDE]]
+; CHECK-NEXT:    ret <2 x i32> [[R]]
+;
+  %shamt_wide = sext <2 x i8> %shamt to <2 x i32>
+  %r = shl <2 x i32> %x, %shamt_wide
+  ret <2 x i32> %r
+}
+define <2 x i32> @t4_vec_lshr(<2 x i32> %x, <2 x i8> %shamt) {
+; CHECK-LABEL: @t4_vec_lshr(
+; CHECK-NEXT:    [[SHAMT_WIDE:%.*]] = sext <2 x i8> [[SHAMT:%.*]] to <2 x i32>
+; CHECK-NEXT:    [[R:%.*]] = lshr <2 x i32> [[X:%.*]], [[SHAMT_WIDE]]
+; CHECK-NEXT:    ret <2 x i32> [[R]]
+;
+  %shamt_wide = sext <2 x i8> %shamt to <2 x i32>
+  %r = lshr <2 x i32> %x, %shamt_wide
+  ret <2 x i32> %r
+}
+define <2 x i32> @t5_vec_ashr(<2 x i32> %x, <2 x i8> %shamt) {
+; CHECK-LABEL: @t5_vec_ashr(
+; CHECK-NEXT:    [[SHAMT_WIDE:%.*]] = sext <2 x i8> [[SHAMT:%.*]] to <2 x i32>
+; CHECK-NEXT:    [[R:%.*]] = ashr <2 x i32> [[X:%.*]], [[SHAMT_WIDE]]
+; CHECK-NEXT:    ret <2 x i32> [[R]]
+;
+  %shamt_wide = sext <2 x i8> %shamt to <2 x i32>
+  %r = ashr <2 x i32> %x, %shamt_wide
+  ret <2 x i32> %r
+}
+
+; This is not valid for funnel shifts
+declare i32 @llvm.fshl.i32(i32 %a, i32 %b, i32 %c)
+declare i32 @llvm.fshr.i32(i32 %a, i32 %b, i32 %c)
+define i32 @n6_fshl(i32 %x, i32 %y, i8 %shamt) {
+; CHECK-LABEL: @n6_fshl(
+; CHECK-NEXT:    [[SHAMT_WIDE1:%.*]] = zext i8 [[SHAMT:%.*]] to i32
+; CHECK-NEXT:    [[R:%.*]] = call i32 @llvm.fshl.i32(i32 [[X:%.*]], i32 [[Y:%.*]], i32 [[SHAMT_WIDE1]])
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %shamt_wide = sext i8 %shamt to i32
+  %r = call i32 @llvm.fshl.i32(i32 %x, i32 %y, i32 %shamt_wide)
+  ret i32 %r
+}
+define i32 @n7_fshr(i32 %x, i32 %y, i8 %shamt) {
+; CHECK-LABEL: @n7_fshr(
+; CHECK-NEXT:    [[SHAMT_WIDE1:%.*]] = zext i8 [[SHAMT:%.*]] to i32
+; CHECK-NEXT:    [[R:%.*]] = call i32 @llvm.fshr.i32(i32 [[X:%.*]], i32 [[Y:%.*]], i32 [[SHAMT_WIDE1]])
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %shamt_wide = sext i8 %shamt to i32
+  %r = call i32 @llvm.fshr.i32(i32 %x, i32 %y, i32 %shamt_wide)
+  ret i32 %r
+}
+
+declare void @use32(i32)
+define i32 @n8_extrause(i32 %x, i8 %shamt) {
+; CHECK-LABEL: @n8_extrause(
+; CHECK-NEXT:    [[SHAMT_WIDE:%.*]] = sext i8 [[SHAMT:%.*]] to i32
+; CHECK-NEXT:    call void @use32(i32 [[SHAMT_WIDE]])
+; CHECK-NEXT:    [[R:%.*]] = shl i32 [[X:%.*]], [[SHAMT_WIDE]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %shamt_wide = sext i8 %shamt to i32
+  call void @use32(i32 %shamt_wide)
+  %r = shl i32 %x, %shamt_wide
+  ret i32 %r
+}