https://github.com/llvm-beanz created
https://github.com/llvm/llvm-project/pull/106811
DXC prefers dimension-preserving conversions over precision-losing conversions.
This means a double4 -> float4 conversion is preferred over a double4 ->
double3 or double4 -> double conversion.
>From 4abb34b1b21e666e20a9b3bad8af146d3bf322f0 Mon Sep 17 00:00:00 2001
From: Chris Bieneman <cbiene...@microsoft.com>
Date: Fri, 30 Aug 2024 23:54:41 +0000
Subject: [PATCH] Fix implicit conversion rank ordering
DXC prefers dimension-preserving conversions over precision-losing
conversions. This means a double4 -> float4 conversion is preferred over
a double4 -> double3 or double4 -> double conversion.
---
clang/include/clang/Sema/Overload.h | 6 ++--
.../TruncationOverloadResolution.hlsl | 28 +++++++++----------
2 files changed, 16 insertions(+), 18 deletions(-)
diff --git a/clang/include/clang/Sema/Overload.h
b/clang/include/clang/Sema/Overload.h
index d6a6cee62a7528..f63f48e0fa3048 100644
--- a/clang/include/clang/Sema/Overload.h
+++ b/clang/include/clang/Sema/Overload.h
@@ -225,12 +225,12 @@ class Sema;
/// HLSL Scalar Widening with promotion
ICR_HLSL_Scalar_Widening_Promotion,
- /// HLSL Matching Dimension Reduction
- ICR_HLSL_Dimension_Reduction,
-
/// Conversion
ICR_Conversion,
+ /// HLSL Matching Dimension Reduction
+ ICR_HLSL_Dimension_Reduction,
+
/// OpenCL Scalar Widening
ICR_OCL_Scalar_Widening,
diff --git a/clang/test/SemaHLSL/TruncationOverloadResolution.hlsl
b/clang/test/SemaHLSL/TruncationOverloadResolution.hlsl
index f8cfe22372e885..2bcb367c5669a3 100644
--- a/clang/test/SemaHLSL/TruncationOverloadResolution.hlsl
+++ b/clang/test/SemaHLSL/TruncationOverloadResolution.hlsl
@@ -1,24 +1,16 @@
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -fnative-half-type
-finclude-default-header -fsyntax-only %s -DERROR=1 -verify
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -fnative-half-type
-finclude-default-header -fsyntax-only -Wconversion %s -DERROR=1 -verify
// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -fnative-half-type
-finclude-default-header -ast-dump %s | FileCheck %s
-// Case 1: Prefer exact-match truncation over conversion.
-void Half4Float4Double2(double2 D);
-void Half4Float4Double2(float4 D);
-void Half4Float4Double2(half4 D);
+// Case 1: Prefer conversion over exact match truncation.
void Half4Float2(float2 D);
void Half4Float2(half4 D);
void Case1(float4 F, double4 D) {
// CHECK: CallExpr {{.*}} 'void'
- // CHECK-NEXT: ImplicitCastExpr {{.*}} 'void (*)(double2)'
<FunctionToPointerDecay>
- // CHECK-NEXT: DeclRefExpr {{.*}} 'void (double2)' lvalue Function {{.*}}
'Half4Float4Double2' 'void (double2)'
- Half4Float4Double2(D); // expected-warning{{implicit conversion truncates
vector: 'double4' (aka 'vector<double, 4>') to 'vector<double, 2>' (vector of 2
'double' values)}}
-
- // CHECK: CallExpr {{.*}} 'void'
- // CHECK-NEXT: ImplicitCastExpr {{.*}} 'void (*)(float2)'
<FunctionToPointerDecay>
- // CHECK-NEXT: DeclRefExpr {{.*}} 'void (float2)' lvalue Function {{.*}}
'Half4Float2' 'void (float2)'
- Half4Float2(F); // expected-warning{{implicit conversion truncates vector:
'float4' (aka 'vector<float, 4>') to 'vector<float, 2>' (vector of 2 'float'
values)}}
+ // CHECK-NEXT: ImplicitCastExpr {{.*}} 'void (*)(half4)'
<FunctionToPointerDecay>
+ // CHECK-NEXT: DeclRefExpr {{.*}} 'void (half4)' lvalue Function {{.*}}
'Half4Float2' 'void (half4)'
+ Half4Float2(F); // expected-warning{{implicit conversion loses
floating-point precision: 'float4' (aka 'vector<float, 4>') to 'vector<half,
4>' (vector of 4 'half' values)}}
}
// Case 2: Prefer promotions over conversions when truncating.
@@ -46,7 +38,13 @@ void Half2Half3(half2 D); // expected-note{{candidate
function}} expected-note{{
void Double2Double3(double3 D); // expected-note{{candidate function}}
expected-note{{candidate function}} expected-note{{candidate function}}
void Double2Double3(double2 D); // expected-note{{candidate function}}
expected-note{{candidate function}} expected-note{{candidate function}}
+void Half4Float4Double2(double2 D);
+void Half4Float4Double2(float4 D); // expected-note{{candidate function}}
+void Half4Float4Double2(half4 D); // expected-note{{candidate function}}
+
void Case1(half4 H, float4 F, double4 D) {
+ Half4Float4Double2(D); // expected-error {{call to 'Half4Float4Double2' is
ambiguous}}
+
Float2Double2(H); // expected-error {{call to 'Float2Double2' is ambiguous}}
Half2Float2(D); // expected-error {{call to 'Half2Float2' is ambiguous}}
@@ -55,8 +53,8 @@ void Case1(half4 H, float4 F, double4 D) {
Half2Half3(F); // expected-error {{call to 'Half2Half3' is ambiguous}}
Half2Half3(D); // expected-error {{call to 'Half2Half3' is ambiguous}}
Half2Half3(H.xyz);
- Half2Half3(F.xyz);
- Half2Half3(D.xyz);
+ Half2Half3(F.xyz); // expected-warning {{implicit conversion loses
floating-point precision: 'vector<float, 3>' (vector of 3 'float' values) to
'vector<half, 3>' (vector of 3 'half' values)}}
+ Half2Half3(D.xyz); // expected-warning {{implicit conversion loses
floating-point precision: 'vector<double, 3>' (vector of 3 'double' values) to
'vector<half, 3>' (vector of 3 'half' values)}}
Double2Double3(H); // expected-error {{call to 'Double2Double3' is
ambiguous}}
Double2Double3(F); // expected-error {{call to 'Double2Double3' is
ambiguous}}
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