[clang] Fix implicit conversion rank ordering (PR #106811)
Chris B via cfe-commits
cfe-commits at lists.llvm.org
Fri Aug 30 19:59:12 PDT 2024
https://github.com/llvm-beanz updated https://github.com/llvm/llvm-project/pull/106811
>From 4abb34b1b21e666e20a9b3bad8af146d3bf322f0 Mon Sep 17 00:00:00 2001
From: Chris Bieneman <cbieneman at microsoft.com>
Date: Fri, 30 Aug 2024 23:54:41 +0000
Subject: [PATCH 1/2] 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}}
>From 60af644c8fc24fdf8848e645f008317339c1e760 Mon Sep 17 00:00:00 2001
From: Chris Bieneman <cbieneman at microsoft.com>
Date: Sat, 31 Aug 2024 02:56:20 +0000
Subject: [PATCH 2/2] Minor tweak to align code with the language spec
This is an NFC change. For a given argument in a call there cannot be a
valid implicit conversion seqeunce of any of the scalar widening ranks
and a conversion sequence for a different overload of dimension
reduction because the widening ranks require the argument to be a scalar
and the reduction ranks require the argument to be a vector.
Changing the order in this change does not impact behavior in any way,
but it does align the source with the spec's language and ordering which
makes it cleaner to read.
---
clang/include/clang/Sema/Overload.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/clang/include/clang/Sema/Overload.h b/clang/include/clang/Sema/Overload.h
index f63f48e0fa3048..c716a25bb673b8 100644
--- a/clang/include/clang/Sema/Overload.h
+++ b/clang/include/clang/Sema/Overload.h
@@ -228,9 +228,6 @@ class Sema;
/// Conversion
ICR_Conversion,
- /// HLSL Matching Dimension Reduction
- ICR_HLSL_Dimension_Reduction,
-
/// OpenCL Scalar Widening
ICR_OCL_Scalar_Widening,
@@ -250,6 +247,9 @@ class Sema;
/// extension anyway.
ICR_C_Conversion_Extension,
+ /// HLSL Matching Dimension Reduction
+ ICR_HLSL_Dimension_Reduction,
+
/// HLSL Dimension reduction with promotion
ICR_HLSL_Dimension_Reduction_Promotion,
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