[SYCL][Sema] Only imply float size conversion warnings in SYCL (#16857)

Before this change `-Wimplicit-float-conversion` (part of `-Wconversion`) enabled `-Wimplicit-float-size-conversion` for all language modes. This is problematic because it causes DPC++ to emit warnings where upstream clang does not, even when used as a plain C++ compiler. Projects that enable `-Werror` don't expect these (questionable) floating point size warnings when they enable `-Wconversion`, and as such cannot be compiled with the DPC++ compiler. Change `-Wimplicit-float-conversion` to only be emitted in SYCL language mode and rename it to `-Wsycl-implicit-float-conversion`. This preserves existing behaviour for SYCL users, but otherwise matches upstream Clang behaviour. Fixes: #16393
intel · Feb 14, 2025 · 254dd3b · 254dd3b
1 parent fdea2cb
commit 254dd3b
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Showing 10 changed files with 39 additions and 29 deletions.
diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -115,11 +115,10 @@ def ImplicitIntFloatConversion : DiagGroup<"implicit-int-float-conversion",
  [ImplicitConstIntFloatConversion]>;
 def ObjCSignedCharBoolImplicitFloatConversion :
   DiagGroup<"objc-signed-char-bool-implicit-float-conversion">;
-def ImplicitFloatSizeConversion :
-  DiagGroup<"implicit-float-size-conversion">;
+def SyclImplicitFloatSizeConversion : DiagGroup<"sycl-implicit-float-size-conversion">;
 def ImplicitFloatConversion : DiagGroup<"implicit-float-conversion",
   [ImplicitIntFloatConversion,
-   ObjCSignedCharBoolImplicitFloatConversion, ImplicitFloatSizeConversion]>;
+   ObjCSignedCharBoolImplicitFloatConversion, SyclImplicitFloatSizeConversion]>;
 def ImplicitFixedPointConversion : DiagGroup<"implicit-fixed-point-conversion">;
 
 def FloatOverflowConversion : DiagGroup<"float-overflow-conversion">;

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -131,9 +131,9 @@ def warn_float_compare_literal : Warning<
 def warn_double_const_requires_fp64 : Warning<
   "double precision constant requires %select{cl_khr_fp64|cl_khr_fp64 and __opencl_c_fp64}0, "
   "casting to single precision">;
-def warn_imp_float_size_conversion : Warning<
+def warn_sycl_imp_float_size_conversion : Warning<
   "implicit conversion between floating point types of different sizes">,
-  InGroup<ImplicitFloatSizeConversion>, DefaultIgnore;
+  InGroup<SyclImplicitFloatSizeConversion>, DefaultIgnore;
 def err_half_const_requires_fp16 : Error<
   "half precision constant requires cl_khr_fp16">;
 

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
@@ -11680,27 +11680,33 @@ void Sema::CheckImplicitConversion(Expr *E, QualType T, SourceLocation CC,
                   result.Val,
                   Context.getFloatTypeSemantics(QualType(TargetBT, 0)),
                   Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) {
-            if (getLangOpts().SYCLIsDevice)
-              SYCL().DiagIfDeviceCode(CC, diag::warn_imp_float_size_conversion);
-            else
-              DiagnoseImpCast(*this, E, T, CC,
-                              diag::warn_imp_float_size_conversion);
+            if (getLangOpts().isSYCL()) {
+              if (getLangOpts().SYCLIsDevice)
+                SYCL().DiagIfDeviceCode(
+                    CC, diag::warn_sycl_imp_float_size_conversion);
+              else
+                DiagnoseImpCast(*this, E, T, CC,
+                                diag::warn_sycl_imp_float_size_conversion);
+            }
             return;
           }
         }
 
         if (SourceMgr.isInSystemMacro(CC))
           return;
         // If there is a precision conversion between floating point types when
-        // -Wimplicit-float-size-conversion is passed but
+        // -Wsycl-implicit-float-size-conversion is passed but
         // -Wimplicit-float-conversion is not, make sure we emit at least a size
         // warning.
         if (Diags.isIgnored(diag::warn_impcast_float_precision, CC)) {
-          if (getLangOpts().SYCLIsDevice)
-            SYCL().DiagIfDeviceCode(CC, diag::warn_imp_float_size_conversion);
-          else
-            DiagnoseImpCast(*this, E, T, CC,
-                            diag::warn_imp_float_size_conversion);
+          if (getLangOpts().isSYCL()) {
+            if (getLangOpts().SYCLIsDevice)
+              SYCL().DiagIfDeviceCode(
+                  CC, diag::warn_sycl_imp_float_size_conversion);
+            else
+              DiagnoseImpCast(*this, E, T, CC,
+                              diag::warn_sycl_imp_float_size_conversion);
+          }
         }
         DiagnoseImpCast(*this, E, T, CC, diag::warn_impcast_float_precision);
       }

diff --git a/clang/test/Sema/conversion.c b/clang/test/Sema/conversion.c
@@ -443,4 +443,3 @@ float double2float_test4(double a, float b) {
   b -= a; // expected-warning {{implicit conversion when assigning computation result loses floating-point precision: 'double' to 'float'}}
   return b;
 }
-float f = 1.0 / 2.0; // expected-warning {{implicit conversion between floating point types of different sizes}}
diff --git a/clang/test/Sema/ext_vector_casts.c b/clang/test/Sema/ext_vector_casts.c
@@ -119,7 +119,7 @@ static void splats(int i, long l, __uint128_t t, float f, double d) {
 
   vf = 1 + vf;
   vf = l + vf; // expected-warning {{implicit conversion from 'long' to 'float2' (vector of 2 'float' values) may lose precision}}
-  vf = 2.0 + vf; // expected-warning {{implicit conversion between floating point types of different sizes}}
+  vf = 2.0 + vf;
   vf = d + vf; // expected-warning {{implicit conversion loses floating-point precision}}
   vf = vf + 0xffffffff; // expected-warning {{implicit conversion from 'unsigned int' to 'float2' (vector of 2 'float' values) changes value from 4294967295 to 4294967296}}
   vf = vf + 2.1; // expected-warning {{implicit conversion loses floating-point precision}}

diff --git a/clang/test/SemaHLSL/Types/Arithmetic/literal_suffixes.hlsl b/clang/test/SemaHLSL/Types/Arithmetic/literal_suffixes.hlsl
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.2-library -fnative-half-type -Wconversion -Wno-implicit-float-size-conversion -verify %s
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.2-library -fnative-half-type -Wconversion -verify %s
 
 void literal_assignments() {
   half h;

diff --git a/clang/test/SemaHLSL/Types/Arithmetic/literal_suffixes_no_16bit.hlsl b/clang/test/SemaHLSL/Types/Arithmetic/literal_suffixes_no_16bit.hlsl
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.2-library -Wconversion -Wno-implicit-float-size-conversion -verify %s
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.2-library -Wconversion -verify %s
 
 void literal_assignments() {
   half h;

diff --git a/clang/test/SemaHLSL/standard_conversion_sequences.hlsl b/clang/test/SemaHLSL/standard_conversion_sequences.hlsl
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -Wconversion -Wno-implicit-float-size-conversion -verify -o - %s
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -Wno-conversion -Wno-implicit-float-size-conversion -DNO_ERR -ast-dump %s | FileCheck %s
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -Wconversion -verify -o - %s
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -Wno-conversion -DNO_ERR -ast-dump %s | FileCheck %s
 
 void test() {
 

diff --git a/clang/test/SemaSYCL/implicit-float-size-conversion.cpp b/clang/test/SemaSYCL/implicit-float-size-conversion.cpp
@@ -1,6 +1,6 @@
-// RUN: %clang_cc1 -fsycl-is-device -triple spir64 -internal-isystem %S/Inputs -fsyntax-only -sycl-std=2020 -Wimplicit-float-size-conversion -verify=size-only,always-size %s
+// RUN: %clang_cc1 -fsycl-is-device -triple spir64 -internal-isystem %S/Inputs -fsyntax-only -sycl-std=2020 -Wsycl-implicit-float-size-conversion -verify=size-only,always-size %s
 // RUN: %clang_cc1 -fsycl-is-device -triple spir64 -internal-isystem %S/Inputs -fsyntax-only -sycl-std=2020 -Wimplicit-float-conversion -verify=always-size,precision-only %s
-// RUN: %clang_cc1 -fsycl-is-device -triple spir64 -internal-isystem %S/Inputs -fsyntax-only -sycl-std=2020 -Wimplicit-float-conversion -Wno-implicit-float-size-conversion -verify=prefer-precision %s
+// RUN: %clang_cc1 -fsycl-is-device -triple spir64 -internal-isystem %S/Inputs -fsyntax-only -sycl-std=2020 -Wimplicit-float-conversion -Wno-sycl-implicit-float-size-conversion -verify=prefer-precision %s
 // RUN: %clang_cc1 -fsycl-is-device -triple spir64 -internal-isystem %S/Inputs -fsyntax-only -sycl-std=2020 -Wno-implicit-float-conversion -verify %s
 
 // This test checks that floating point conversion warnings are emitted correctly when used in conjunction.

diff --git a/...test/Sema/precision-and-size-conversion.c → .../SemaSYCL/precision-and-size-conversion.c b/...test/Sema/precision-and-size-conversion.c → .../SemaSYCL/precision-and-size-conversion.c
@@ -1,16 +1,22 @@
-// RUN: %clang_cc1 -fsyntax-only -verify=precision-loss,precision-gain,size-change -Wimplicit-float-conversion -Wdouble-promotion -Wimplicit-float-size-conversion \
+// RUN: %clang_cc1 -fsyntax-only -verify=precision-loss,precision-gain,size-change -fsycl-is-host -Wimplicit-float-conversion -Wdouble-promotion -Wsycl-implicit-float-size-conversion \
 // RUN:   -triple x86_64-apple-darwin %s
 
-// RUN: %clang_cc1 -fsyntax-only -verify=size-only,precision-gain,size-change -Wdouble-promotion -Wimplicit-float-size-conversion \
+// RUN: %clang_cc1 -fsyntax-only -verify=size-only,precision-gain,size-change -fsycl-is-host -Wdouble-promotion -Wsycl-implicit-float-size-conversion \
 // RUN:   -triple x86_64-apple-darwin %s
 
-// RUN: %clang_cc1 -fsyntax-only -verify=precision-increase -Wdouble-promotion \
+// RUN: %clang_cc1 -fsyntax-only -verify=precision-increase -fsycl-is-host -Wdouble-promotion \
 // RUN:   -triple x86_64-apple-darwin %s
 
-// RUN: %clang_cc1 -fsyntax-only -verify=precision-loss,size-change -Wimplicit-float-conversion \
+// RUN: %clang_cc1 -fsyntax-only -verify=precision-loss,size-change -fsycl-is-host -Wimplicit-float-conversion \
 // RUN:   -triple x86_64-apple-darwin %s
 
-// RUN: %clang_cc1 -fsyntax-only -verify \
+// RUN: %clang_cc1 -fsyntax-only -verify=precision-loss -Wimplicit-float-conversion \
+// RUN:   -triple x86_64-apple-darwin %s
+
+// RUN: %clang_cc1 -fsyntax-only -verify -fsycl-is-host \
+// RUN:   -triple x86_64-apple-darwin %s
+
+// RUN: %clang_cc1 -fsyntax-only -verify -Wsycl-implicit-float-size-conversion \
 // RUN:   -triple x86_64-apple-darwin %s
 
 // This test checks that floating point conversion warnings are emitted correctly when used in conjunction.