[clang] [llvm] [HLSL] [DXIL] Implement the AddUint64 HLSL function and the UAddc DXIL op (PR #127137)

[Deric Cheung via llvm-commits]

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@@ -0,0 +1,71 @@
+; RUN: opt -S -scalarizer -dxil-op-lower -mtriple=dxil-pc-shadermodel6.3-library %s | FileCheck %s
+
+; CHECK: %dx.types.i32c = type { i32, i1 }
+
+define noundef i32 @test_UAddc(i32 noundef %a, i32 noundef %b) {
+; CHECK-LABEL: define noundef i32 @test_UAddc(
+; CHECK-SAME: i32 noundef [[A:%.*]], i32 noundef [[B:%.*]]) {
+; CHECK-NEXT:    [[UADDC:%.*]] = call [[DX_TYPES_I32C:%dx\.types\.i32c]] @dx.op.binaryWithCarryOrBorrow.i32(i32 44, i32 [[A]], i32 [[B]]) #[[ATTR0:[0-9]+]]
+; CHECK-NEXT:    [[CARRY:%.*]] = extractvalue [[DX_TYPES_I32C]] [[UADDC]], 1
+; CHECK-NEXT:    [[SUM:%.*]] = extractvalue [[DX_TYPES_I32C]] [[UADDC]], 0
+; CHECK-NEXT:    [[CARRY_ZEXT:%.*]] = zext i1 [[CARRY]] to i32
+; CHECK-NEXT:    [[RESULT:%.*]] = add i32 [[SUM]], [[CARRY_ZEXT]]
+; CHECK-NEXT:    ret i32 [[RESULT]]
+;
+  %uaddc = call { i32, i1 } @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
+  %carry = extractvalue { i32, i1 } %uaddc, 1
+  %sum = extractvalue { i32, i1 } %uaddc, 0
+  %carry_zext = zext i1 %carry to i32
+  %result = add i32 %sum, %carry_zext
+  ret i32 %result
+}
+
+define noundef <2 x i32> @test_UAddc_vec2(<2 x i32> noundef %a, <2 x i32> noundef %b) {
+; CHECK-LABEL: define noundef <2 x i32> @test_UAddc_vec2(
+; CHECK-SAME: <2 x i32> noundef [[A:%.*]], <2 x i32> noundef [[B:%.*]]) {
+; CHECK-NEXT:    [[A_I0:%.*]] = extractelement <2 x i32> [[A]], i64 0
+; CHECK-NEXT:    [[B_I0:%.*]] = extractelement <2 x i32> [[B]], i64 0
+; CHECK-NEXT:    [[UADDC_I0:%.*]] = call [[DX_TYPES_I32C:%dx\.types\.i32c]] @dx.op.binaryWithCarryOrBorrow.i32(i32 44, i32 [[A_I0]], i32 [[B_I0]]) #[[ATTR0]]
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Icohedron wrote:

The `uint2` version of `AddUint64` calls `@llvm.uadd.with.overflow.i32` which translates into one `@dx.op.binaryWithCarryOrBorrow.i32`.
The `uint4` version of `AddUint64` calls `@llvm.uadd.with.overflow.v2i32` which translates into two `@dx.op.binaryWithCarryOrBorrow.i32`.

https://github.com/llvm/llvm-project/pull/127137