[llvm] [DirectX] Start the creation of a DXIL Instruction legalizer (PR #131221)

[Farzon Lotfi via llvm-commits]

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@@ -0,0 +1,109 @@
+; RUN: opt -S -passes='dxil-legalize' -mtriple=dxil-pc-shadermodel6.3-library %s | FileCheck %s
+
+define i32 @removal_only_test(i32 %a) {
+  ; CHECK-LABEL: define i32 @removal_only_test(
+  ; CHECK-SAME: i32 [[A:%.*]]) {
+  ; CHECK: ret i32 [[A]]
+  %1 = trunc nsw i32 %a to i8
+  %3 = sext i8 %1 to i32
+  ret i32 %3
+}
+
+define i32 @i8trunc(float %0) #0 {
+  ; CHECK-LABEL: define i32 @i8trunc(
+  ; CHECK-NOT: %4 = trunc nsw i32 %3 to i8
+  ; CHECK: add nsw i32
+  ; CHECK-NEXT: srem i32
+  ; CHECK-NEXT: sub i32
+  ; CHECK-NEXT: mul i32
+  ; CHECK-NEXT: udiv i32
+  ; CHECK-NEXT: sdiv i32
+  ; CHECK-NEXT: urem i32
+  ; CHECK-NEXT: and i32
+  ; CHECK-NEXT: or i32
+  ; CHECK-NEXT: xor i32
+  ; CHECK-NEXT: shl i32
+  ; CHECK-NEXT: lshr i32
+  ; CHECK-NEXT: ashr i32
+  ; CHECK-NOT: %7 = sext i8 %6 to i32
+  
+  %2 = fptosi float %0 to i32
+  %3 = srem i32 %2, 8
+  %4 = trunc nsw i32 %3 to i8
+  %5 = add nsw i8 %4, 1
+  %6 = srem i8 %5, 8
+  %7 = sub i8 %6, 1
+  %8 = mul i8 %7, 1
+  %9 = udiv i8 %8, 1
+  %10 = sdiv i8 %9, 1
+  %11 = urem i8 %10, 1
+  %12 = and i8 %11, 1
+  %13 = or i8 %12, 1
+  %14 = xor i8 %13, 1
+  %15 = shl i8 %14, 1
+  %16 = lshr i8 %15, 1
+  %17 = ashr i8 %16, 1
+  %18 = sext i8 %17 to i32
+  ret i32 %18
+}
+
+define i32 @cast_removal_test(i32 %a) {
+  ; CHECK-LABEL: define i32 @cast_removal_test(
+  ; CHECK-SAME: i32 [[A:%.*]]) {
+  ; CHECK-NOT: trunc
+  ; CHECK-NOT: zext i8
+  ; CHECK-NOT: sext i8
+  ; CHECK: add i32 [[A]], [[A]]
+  %1 = trunc nsw i32 %a to i8
+  %2 = zext i8 %1 to i32
+  %3 = sext i8 %1 to i32
+  %4 = add i32 %2, %3
+  ret i32 %4
+}
+
+define i1 @trunc_cmp_test(i32 %a, i32 %b) {
+  ; CHECK-LABEL: define i1 @trunc_cmp_test(
+  ; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]]) {
+  ; CHECK: icmp slt i32 [[A]], [[B]]
+  ; CHECK: icmp sgt i32 [[A]], [[B]]
+  %1 = trunc nsw i32 %a to i8
+  %2 = trunc nsw i32 %b to i8
+  %3 = icmp slt i8 %1, %2
+  %4 = icmp sgt i8 %1, %2
+  %5 = and i1 %3, %4
+  ret i1 %5
+}
+
+define i32 @first_operand_imm_test(i32 %a) {
+  ; CHECK-LABEL: define i32 @first_operand_imm_test(
+  ; CHECK-SAME: i32 [[A:%.*]]) {
+  ; CHECK-NOT: trunc
+  ; CHECK: sub i32 0, [[A]]
+  ; CHECK-NOT: sext i8
+  %1 = trunc nsw i32 %a to i8
+  %2 = sub i8 0, %1
+  %3 = sext i8 %2 to i32
+  ret i32 %3
+}
+
+define i16 @i16_test(i16 %a) {
+  ; CHECK-LABEL: define i16 @i16_test(
+  ; CHECK-SAME: i16 [[A:%.*]]) {
+  ; CHECK-NOT: trunc
+  ; CHECK: sub i16 0, [[A]]
+  ; CHECK-NOT: sext i8
+  %1 = trunc nsw i16 %a to i8
+  %2 = sub i8 0, %1
+  %3 = sext i8 %2 to i16
+  ret i16 %3
+}
+
+define i32 @all_imm() {
+  ; CHECK-LABEL: define i32 @all_imm(
+  ; CHECK-NOT: trunc
----------------
farzonl wrote:

delete no trunc in this case.

https://github.com/llvm/llvm-project/pull/131221