zahiraam updated this revision to Diff 417279.
zahiraam marked 5 inline comments as done.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D122155/new/
https://reviews.llvm.org/D122155
Files:
clang/include/clang/Basic/DiagnosticCommonKinds.td
clang/lib/Sema/Sema.cpp
clang/lib/Sema/SemaAttr.cpp
clang/test/Sema/eval-method-with-unsafe-math.c
Index: clang/test/Sema/eval-method-with-unsafe-math.c
===================================================================
--- /dev/null
+++ clang/test/Sema/eval-method-with-unsafe-math.c
@@ -0,0 +1,28 @@
+// RUN: %clang_cc1 -fexperimental-strict-floating-point \
+// RUN: -triple x86_64-linux-gnu -ffp-eval-method=source \
+// RUN: -verify %s
+
+// RUN: %clang_cc1 -fexperimental-strict-floating-point \
+// RUN: -triple x86_64-linux-gnu -fapprox-func -ffp-eval-method=source \
+// RUN: %s 2>&1 | FileCheck %s --check-prefix=WARN
+
+// RUN: %clang_cc1 -fexperimental-strict-floating-point \
+// RUN: -triple x86_64-linux-gnu -freciprocal-math -ffp-eval-method=source \
+// RUN: %s 2>&1 | FileCheck %s --check-prefix=WARN
+
+// RUN: %clang_cc1 -fexperimental-strict-floating-point \
+// RUN: -triple x86_64-linux-gnu -mreassociate -ffp-eval-method=source \
+// RUN: %s 2>&1 | FileCheck %s --check-prefix=WARN
+
+// expected-no-diagnostics
+
+float f1(float a, float b, float c) {
+ return a * b + c;
+ // WARN: setting the eval method via the '-ffp-eval-method' option or
'#pragma clang fp eval_method' has not effect when numeric results of
floating-point calculations aren't value-safe.
+}
+
+float f2(float a, float b, float c) {
+#pragma clang fp eval_method(double)
+ // WARN: setting the eval method via the '-ffp-eval-method' option or
'#pragma clang fp eval_method' has not effect when numeric results of
floating-point calculations aren't value-safe.
+ return a * b + c;
+}
Index: clang/lib/Sema/SemaAttr.cpp
===================================================================
--- clang/lib/Sema/SemaAttr.cpp
+++ clang/lib/Sema/SemaAttr.cpp
@@ -486,6 +486,10 @@
NewFPFeatures.setFPEvalMethodOverride(LangOptions::FEM_Extended);
break;
}
+ if (getLangOpts().ApproxFunc || getLangOpts().AllowFPReassoc ||
+ getLangOpts().AllowRecip)
+ Diags.Report(
+ diag::warn_eval_method_setting_is_meaningless_in_value_unsafe_context);
FpPragmaStack.Act(Loc, PSK_Set, StringRef(), NewFPFeatures);
CurFPFeatures = NewFPFeatures.applyOverrides(getLangOpts());
PP.setCurrentFPEvalMethod(Loc, Value);
Index: clang/lib/Sema/Sema.cpp
===================================================================
--- clang/lib/Sema/Sema.cpp
+++ clang/lib/Sema/Sema.cpp
@@ -252,10 +252,22 @@
// Use setting from TargetInfo.
PP.setCurrentFPEvalMethod(SourceLocation(),
ctxt.getTargetInfo().getFPEvalMethod());
- else
+ else {
// Set initial value of __FLT_EVAL_METHOD__ from the command line.
PP.setCurrentFPEvalMethod(SourceLocation(),
getLangOpts().getFPEvalMethod());
+ if (getLangOpts().ApproxFunc || getLangOpts().AllowFPReassoc ||
+ getLangOpts().AllowRecip)
+ // When these options are used, the compiler is allowed to make
+ // transformation that may affect the final result. For example
+ // (x+y)+z is transformed to x+(y+z) but may not give the same
+ // final result; it's not value safe.
+ // Another example can be to simlify x/x to 1.0 but x could be 0.0, INF
+ // or NaN. Final result may then differ.
+ Diags.Report(
+ diag::
+ warn_eval_method_setting_is_meaningless_in_value_unsafe_context);
+ }
CurFPFeatures.setFPEvalMethod(PP.getCurrentFPEvalMethod());
}
Index: clang/include/clang/Basic/DiagnosticCommonKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticCommonKinds.td
+++ clang/include/clang/Basic/DiagnosticCommonKinds.td
@@ -124,6 +124,9 @@
"'consteval' specifier is incompatible with C++ standards before C++20">,
InGroup<CXX20Compat>, DefaultIgnore;
+def warn_eval_method_setting_is_meaningless_in_value_unsafe_context : Warning<
+ "setting the eval method via '-ffp-eval-method' or '#pragma clang fp
eval_method' "
+ "has not effect when numeric results of floating-point calculations aren't
value-safe.">, InGroup<Pragmas>;
}
let CategoryName = "Nullability Issue" in {
Index: clang/test/Sema/eval-method-with-unsafe-math.c
===================================================================
--- /dev/null
+++ clang/test/Sema/eval-method-with-unsafe-math.c
@@ -0,0 +1,28 @@
+// RUN: %clang_cc1 -fexperimental-strict-floating-point \
+// RUN: -triple x86_64-linux-gnu -ffp-eval-method=source \
+// RUN: -verify %s
+
+// RUN: %clang_cc1 -fexperimental-strict-floating-point \
+// RUN: -triple x86_64-linux-gnu -fapprox-func -ffp-eval-method=source \
+// RUN: %s 2>&1 | FileCheck %s --check-prefix=WARN
+
+// RUN: %clang_cc1 -fexperimental-strict-floating-point \
+// RUN: -triple x86_64-linux-gnu -freciprocal-math -ffp-eval-method=source \
+// RUN: %s 2>&1 | FileCheck %s --check-prefix=WARN
+
+// RUN: %clang_cc1 -fexperimental-strict-floating-point \
+// RUN: -triple x86_64-linux-gnu -mreassociate -ffp-eval-method=source \
+// RUN: %s 2>&1 | FileCheck %s --check-prefix=WARN
+
+// expected-no-diagnostics
+
+float f1(float a, float b, float c) {
+ return a * b + c;
+ // WARN: setting the eval method via the '-ffp-eval-method' option or '#pragma clang fp eval_method' has not effect when numeric results of floating-point calculations aren't value-safe.
+}
+
+float f2(float a, float b, float c) {
+#pragma clang fp eval_method(double)
+ // WARN: setting the eval method via the '-ffp-eval-method' option or '#pragma clang fp eval_method' has not effect when numeric results of floating-point calculations aren't value-safe.
+ return a * b + c;
+}
Index: clang/lib/Sema/SemaAttr.cpp
===================================================================
--- clang/lib/Sema/SemaAttr.cpp
+++ clang/lib/Sema/SemaAttr.cpp
@@ -486,6 +486,10 @@
NewFPFeatures.setFPEvalMethodOverride(LangOptions::FEM_Extended);
break;
}
+ if (getLangOpts().ApproxFunc || getLangOpts().AllowFPReassoc ||
+ getLangOpts().AllowRecip)
+ Diags.Report(
+ diag::warn_eval_method_setting_is_meaningless_in_value_unsafe_context);
FpPragmaStack.Act(Loc, PSK_Set, StringRef(), NewFPFeatures);
CurFPFeatures = NewFPFeatures.applyOverrides(getLangOpts());
PP.setCurrentFPEvalMethod(Loc, Value);
Index: clang/lib/Sema/Sema.cpp
===================================================================
--- clang/lib/Sema/Sema.cpp
+++ clang/lib/Sema/Sema.cpp
@@ -252,10 +252,22 @@
// Use setting from TargetInfo.
PP.setCurrentFPEvalMethod(SourceLocation(),
ctxt.getTargetInfo().getFPEvalMethod());
- else
+ else {
// Set initial value of __FLT_EVAL_METHOD__ from the command line.
PP.setCurrentFPEvalMethod(SourceLocation(),
getLangOpts().getFPEvalMethod());
+ if (getLangOpts().ApproxFunc || getLangOpts().AllowFPReassoc ||
+ getLangOpts().AllowRecip)
+ // When these options are used, the compiler is allowed to make
+ // transformation that may affect the final result. For example
+ // (x+y)+z is transformed to x+(y+z) but may not give the same
+ // final result; it's not value safe.
+ // Another example can be to simlify x/x to 1.0 but x could be 0.0, INF
+ // or NaN. Final result may then differ.
+ Diags.Report(
+ diag::
+ warn_eval_method_setting_is_meaningless_in_value_unsafe_context);
+ }
CurFPFeatures.setFPEvalMethod(PP.getCurrentFPEvalMethod());
}
Index: clang/include/clang/Basic/DiagnosticCommonKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticCommonKinds.td
+++ clang/include/clang/Basic/DiagnosticCommonKinds.td
@@ -124,6 +124,9 @@
"'consteval' specifier is incompatible with C++ standards before C++20">,
InGroup<CXX20Compat>, DefaultIgnore;
+def warn_eval_method_setting_is_meaningless_in_value_unsafe_context : Warning<
+ "setting the eval method via '-ffp-eval-method' or '#pragma clang fp eval_method' "
+ "has not effect when numeric results of floating-point calculations aren't value-safe.">, InGroup<Pragmas>;
}
let CategoryName = "Nullability Issue" in {
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