[flang][Driver] Add support for -f[no-]wrapv and -f[no]-strict-overflow in the frontend #110061

yus3710-fj · 2024-09-26T00:21:45Z

This patch introduces the options for integer overflow flags into Flang.
The behavior is similar to that of Clang.

llvmbot · 2024-10-03T04:15:47Z

@llvm/pr-subscribers-flang-driver

@llvm/pr-subscribers-clang-driver

Author: Yusuke MINATO (yus3710-fj)

Changes

This patch introduces the options for integer overflow flags into Flang.
The behavior is similar to that of Clang.

Full diff: https://github.com/llvm/llvm-project/pull/110061.diff

8 Files Affected:

(modified) clang/include/clang/Driver/Options.td (+7-4)
(modified) clang/lib/Driver/ToolChains/Flang.cpp (+11)
(modified) flang/include/flang/Common/LangOptions.def (+2)
(modified) flang/include/flang/Common/LangOptions.h (+8)
(modified) flang/include/flang/Lower/LoweringOptions.def (+2-3)
(modified) flang/lib/Frontend/CompilerInvocation.cpp (+33-3)
(modified) flang/test/Driver/frontend-forwarding.f90 (+2)
(added) flang/test/Driver/integer-overflow.f90 (+10)

diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 9d183ff2d69b3c..4610cd917f685d 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -3451,7 +3451,8 @@ def fno_strict_aliasing : Flag<["-"], "fno-strict-aliasing">, Group<f_Group>,
 def fstruct_path_tbaa : Flag<["-"], "fstruct-path-tbaa">, Group<f_Group>;
 def fno_struct_path_tbaa : Flag<["-"], "fno-struct-path-tbaa">, Group<f_Group>;
 def fno_strict_enums : Flag<["-"], "fno-strict-enums">, Group<f_Group>;
-def fno_strict_overflow : Flag<["-"], "fno-strict-overflow">, Group<f_Group>;
+def fno_strict_overflow : Flag<["-"], "fno-strict-overflow">, Group<f_Group>,
+  Visibility<[ClangOption, FlangOption]>;
 def fno_pointer_tbaa : Flag<["-"], "fno-pointer-tbaa">, Group<f_Group>;
 def fno_temp_file : Flag<["-"], "fno-temp-file">, Group<f_Group>,
   Visibility<[ClangOption, CC1Option, CLOption, DXCOption]>, HelpText<
@@ -3467,7 +3468,8 @@ def fno_verbose_asm : Flag<["-"], "fno-verbose-asm">, Group<f_Group>,
   Visibility<[ClangOption, CC1Option]>,
   MarshallingInfoNegativeFlag<CodeGenOpts<"AsmVerbose">>;
 def fno_working_directory : Flag<["-"], "fno-working-directory">, Group<f_Group>;
-def fno_wrapv : Flag<["-"], "fno-wrapv">, Group<f_Group>;
+def fno_wrapv : Flag<["-"], "fno-wrapv">, Group<f_Group>,
+  Visibility<[ClangOption, FlangOption]>;
 def fobjc_arc : Flag<["-"], "fobjc-arc">, Group<f_Group>,
   Visibility<[ClangOption, CC1Option]>,
   HelpText<"Synthesize retain and release calls for Objective-C pointers">;
@@ -3963,7 +3965,8 @@ defm strict_vtable_pointers : BoolFOption<"strict-vtable-pointers",
           "Enable optimizations based on the strict rules for"
             " overwriting polymorphic C++ objects">,
   NegFlag<SetFalse>>;
-def fstrict_overflow : Flag<["-"], "fstrict-overflow">, Group<f_Group>;
+def fstrict_overflow : Flag<["-"], "fstrict-overflow">, Group<f_Group>,
+  Visibility<[ClangOption, FlangOption]>;
 def fpointer_tbaa : Flag<["-"], "fpointer-tbaa">, Group<f_Group>;
 def fdriver_only : Flag<["-"], "fdriver-only">, Flags<[NoXarchOption]>,
   Visibility<[ClangOption, CLOption, DXCOption]>,
@@ -4232,7 +4235,7 @@ defm virtual_function_elimination : BoolFOption<"virtual-function-elimination",
   NegFlag<SetFalse>, BothFlags<[], [ClangOption, CLOption]>>;
 
 def fwrapv : Flag<["-"], "fwrapv">, Group<f_Group>,
-  Visibility<[ClangOption, CC1Option]>,
+  Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
   HelpText<"Treat signed integer overflow as two's complement">;
 def fwritable_strings : Flag<["-"], "fwritable-strings">, Group<f_Group>,
   Visibility<[ClangOption, CC1Option]>,
diff --git a/clang/lib/Driver/ToolChains/Flang.cpp b/clang/lib/Driver/ToolChains/Flang.cpp
index 98350690f8d20e..1865fd57a2d893 100644
--- a/clang/lib/Driver/ToolChains/Flang.cpp
+++ b/clang/lib/Driver/ToolChains/Flang.cpp
@@ -866,6 +866,17 @@ void Flang::ConstructJob(Compilation &C, const JobAction &JA,
     }
   }
 
+  // -fno-strict-overflow implies -fwrapv if it isn't disabled, but
+  // -fstrict-overflow won't turn off an explicitly enabled -fwrapv.
+  if (Arg *A = Args.getLastArg(options::OPT_fwrapv, options::OPT_fno_wrapv)) {
+    if (A->getOption().matches(options::OPT_fwrapv))
+      CmdArgs.push_back("-fwrapv");
+  } else if (Arg *A = Args.getLastArg(options::OPT_fstrict_overflow,
+                                      options::OPT_fno_strict_overflow)) {
+    if (A->getOption().matches(options::OPT_fno_strict_overflow))
+      CmdArgs.push_back("-fwrapv");
+  }
+
   assert((Output.isFilename() || Output.isNothing()) && "Invalid output.");
   if (Output.isFilename()) {
     CmdArgs.push_back("-o");
diff --git a/flang/include/flang/Common/LangOptions.def b/flang/include/flang/Common/LangOptions.def
index d3e1e972d1519f..1bfdba9cc2c1c7 100644
--- a/flang/include/flang/Common/LangOptions.def
+++ b/flang/include/flang/Common/LangOptions.def
@@ -20,6 +20,8 @@ LANGOPT(Name, Bits, Default)
 #endif
 
 ENUM_LANGOPT(FPContractMode, FPModeKind, 2, FPM_Fast) ///< FP Contract Mode (off/fast)
+/// signed integer overflow handling
+ENUM_LANGOPT(SignedOverflowBehavior, SignedOverflowBehaviorTy, 1, SOB_Undefined)
 
 /// Indicate a build without the standard GPU libraries.
 LANGOPT(NoGPULib  , 1, false)
diff --git a/flang/include/flang/Common/LangOptions.h b/flang/include/flang/Common/LangOptions.h
index 52a45047deb0e2..83f25cfbe26142 100644
--- a/flang/include/flang/Common/LangOptions.h
+++ b/flang/include/flang/Common/LangOptions.h
@@ -27,6 +27,14 @@ namespace Fortran::common {
 class LangOptionsBase {
 
 public:
+  enum SignedOverflowBehaviorTy {
+    // -fno-wrapv (default behavior in Flang)
+    SOB_Undefined,
+
+    // -fwrapv
+    SOB_Defined,
+  };
+
   enum FPModeKind {
     // Do not fuse FP ops
     FPM_Off,
diff --git a/flang/include/flang/Lower/LoweringOptions.def b/flang/include/flang/Lower/LoweringOptions.def
index d3f17c3f939c16..231de533fbd30a 100644
--- a/flang/include/flang/Lower/LoweringOptions.def
+++ b/flang/include/flang/Lower/LoweringOptions.def
@@ -35,9 +35,8 @@ ENUM_LOWERINGOPT(NoPPCNativeVecElemOrder, unsigned, 1, 0)
 ENUM_LOWERINGOPT(Underscoring, unsigned, 1, 1)
 
 /// If true, assume the behavior of integer overflow is defined
-/// (i.e. wraps around as two's complement). On by default.
-/// TODO: make the default off
-ENUM_LOWERINGOPT(IntegerWrapAround, unsigned, 1, 1)
+/// (i.e. wraps around as two's complement). Off by default.
+ENUM_LOWERINGOPT(IntegerWrapAround, unsigned, 1, 0)
 
 /// If true, add nsw flags to loop variable increments.
 /// Off by default.
diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index 2154b9ab2fbf47..c8160a4236b466 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -1109,6 +1109,24 @@ static bool parseOpenMPArgs(CompilerInvocation &res, llvm::opt::ArgList &args,
   return diags.getNumErrors() == numErrorsBefore;
 }
 
+/// Parses signed integer overflow options and populates the
+/// CompilerInvocation accordingly.
+/// Returns false if new errors are generated.
+///
+/// \param [out] invoc Stores the processed arguments
+/// \param [in] args The compiler invocation arguments to parse
+/// \param [out] diags DiagnosticsEngine to report erros with
+static bool parseIntegerOverflowArgs(CompilerInvocation &invoc,
+                                     llvm::opt::ArgList &args,
+                                     clang::DiagnosticsEngine &diags) {
+  Fortran::common::LangOptions &opts = invoc.getLangOpts();
+
+  if (args.getLastArg(clang::driver::options::OPT_fwrapv))
+    opts.setSignedOverflowBehavior(Fortran::common::LangOptions::SOB_Defined);
+
+  return true;
+}
+
 /// Parses all floating point related arguments and populates the
 /// CompilerInvocation accordingly.
 /// Returns false if new errors are generated.
@@ -1249,6 +1267,18 @@ static bool parseLinkerOptionsArgs(CompilerInvocation &invoc,
   return true;
 }
 
+static bool parseLangOptionsArgs(CompilerInvocation &invoc,
+                                 llvm::opt::ArgList &args,
+                                 clang::DiagnosticsEngine &diags) {
+  bool success = true;
+
+  success &= parseIntegerOverflowArgs(invoc, args, diags);
+  success &= parseFloatingPointArgs(invoc, args, diags);
+  success &= parseVScaleArgs(invoc, args, diags);
+
+  return success;
+}
+
 bool CompilerInvocation::createFromArgs(
     CompilerInvocation &invoc, llvm::ArrayRef<const char *> commandLineArgs,
     clang::DiagnosticsEngine &diags, const char *argv0) {
@@ -1357,9 +1387,7 @@ bool CompilerInvocation::createFromArgs(
   invoc.frontendOpts.mlirArgs =
       args.getAllArgValues(clang::driver::options::OPT_mmlir);
 
-  success &= parseFloatingPointArgs(invoc, args, diags);
-
-  success &= parseVScaleArgs(invoc, args, diags);
+  success &= parseLangOptionsArgs(invoc, args, diags);
 
   success &= parseLinkerOptionsArgs(invoc, args, diags);
 
@@ -1571,6 +1599,8 @@ void CompilerInvocation::setLoweringOptions() {
   loweringOpts.setUnderscoring(codegenOpts.Underscoring);
 
   const Fortran::common::LangOptions &langOptions = getLangOpts();
+  loweringOpts.setIntegerWrapAround(langOptions.getSignedOverflowBehavior() ==
+                                    Fortran::common::LangOptions::SOB_Defined);
   Fortran::common::MathOptionsBase &mathOpts = loweringOpts.getMathOptions();
   // TODO: when LangOptions are finalized, we can represent
   //       the math related options using Fortran::commmon::MathOptionsBase,
diff --git a/flang/test/Driver/frontend-forwarding.f90 b/flang/test/Driver/frontend-forwarding.f90
index 35adb47b56861e..382c1aa5d350b7 100644
--- a/flang/test/Driver/frontend-forwarding.f90
+++ b/flang/test/Driver/frontend-forwarding.f90
@@ -14,6 +14,7 @@
 ! RUN:     -fno-signed-zeros \
 ! RUN:     -fassociative-math \
 ! RUN:     -freciprocal-math \
+! RUN:     -fno-strict-overflow \
 ! RUN:     -fomit-frame-pointer \
 ! RUN:     -fpass-plugin=Bye%pluginext \
 ! RUN:     -fversion-loops-for-stride \
@@ -63,4 +64,5 @@
 ! CHECK: "-Rpass=inline"
 ! CHECK: "-mframe-pointer=none"
 ! CHECK: "-mllvm" "-print-before-all"
+! CHECK: "-fwrapv"
 ! CHECK: "-save-temps=obj"
diff --git a/flang/test/Driver/integer-overflow.f90 b/flang/test/Driver/integer-overflow.f90
new file mode 100644
index 00000000000000..2cfb36527a30ad
--- /dev/null
+++ b/flang/test/Driver/integer-overflow.f90
@@ -0,0 +1,10 @@
+! Test for correct forwarding of integer overflow flags from the compiler driver
+! to the frontend driver
+
+! RUN: %flang -### -fno-strict-overflow %s 2>&1 | FileCheck %s --check-prefixes CHECK,INDUCED
+! RUN: %flang -### -fstrict-overflow %s 2>&1 | FileCheck %s
+! RUN: %flang -### -fno-wrapv %s 2>&1 | FileCheck %s
+! RUN: %flang -### -fno-wrapv -fno-strict-overflow %s 2>&1 | FileCheck %s
+
+! CHECK-NOT: "-fno-wrapv"
+! INDUCED: "-fwrapv"

llvmbot · 2024-10-03T04:15:47Z

@llvm/pr-subscribers-flang-fir-hlfir

Author: Yusuke MINATO (yus3710-fj)

Changes

This patch introduces the options for integer overflow flags into Flang.
The behavior is similar to that of Clang.

Full diff: https://github.com/llvm/llvm-project/pull/110061.diff

8 Files Affected:

(modified) clang/include/clang/Driver/Options.td (+7-4)
(modified) clang/lib/Driver/ToolChains/Flang.cpp (+11)
(modified) flang/include/flang/Common/LangOptions.def (+2)
(modified) flang/include/flang/Common/LangOptions.h (+8)
(modified) flang/include/flang/Lower/LoweringOptions.def (+2-3)
(modified) flang/lib/Frontend/CompilerInvocation.cpp (+33-3)
(modified) flang/test/Driver/frontend-forwarding.f90 (+2)
(added) flang/test/Driver/integer-overflow.f90 (+10)

diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 9d183ff2d69b3c..4610cd917f685d 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -3451,7 +3451,8 @@ def fno_strict_aliasing : Flag<["-"], "fno-strict-aliasing">, Group<f_Group>,
 def fstruct_path_tbaa : Flag<["-"], "fstruct-path-tbaa">, Group<f_Group>;
 def fno_struct_path_tbaa : Flag<["-"], "fno-struct-path-tbaa">, Group<f_Group>;
 def fno_strict_enums : Flag<["-"], "fno-strict-enums">, Group<f_Group>;
-def fno_strict_overflow : Flag<["-"], "fno-strict-overflow">, Group<f_Group>;
+def fno_strict_overflow : Flag<["-"], "fno-strict-overflow">, Group<f_Group>,
+  Visibility<[ClangOption, FlangOption]>;
 def fno_pointer_tbaa : Flag<["-"], "fno-pointer-tbaa">, Group<f_Group>;
 def fno_temp_file : Flag<["-"], "fno-temp-file">, Group<f_Group>,
   Visibility<[ClangOption, CC1Option, CLOption, DXCOption]>, HelpText<
@@ -3467,7 +3468,8 @@ def fno_verbose_asm : Flag<["-"], "fno-verbose-asm">, Group<f_Group>,
   Visibility<[ClangOption, CC1Option]>,
   MarshallingInfoNegativeFlag<CodeGenOpts<"AsmVerbose">>;
 def fno_working_directory : Flag<["-"], "fno-working-directory">, Group<f_Group>;
-def fno_wrapv : Flag<["-"], "fno-wrapv">, Group<f_Group>;
+def fno_wrapv : Flag<["-"], "fno-wrapv">, Group<f_Group>,
+  Visibility<[ClangOption, FlangOption]>;
 def fobjc_arc : Flag<["-"], "fobjc-arc">, Group<f_Group>,
   Visibility<[ClangOption, CC1Option]>,
   HelpText<"Synthesize retain and release calls for Objective-C pointers">;
@@ -3963,7 +3965,8 @@ defm strict_vtable_pointers : BoolFOption<"strict-vtable-pointers",
           "Enable optimizations based on the strict rules for"
             " overwriting polymorphic C++ objects">,
   NegFlag<SetFalse>>;
-def fstrict_overflow : Flag<["-"], "fstrict-overflow">, Group<f_Group>;
+def fstrict_overflow : Flag<["-"], "fstrict-overflow">, Group<f_Group>,
+  Visibility<[ClangOption, FlangOption]>;
 def fpointer_tbaa : Flag<["-"], "fpointer-tbaa">, Group<f_Group>;
 def fdriver_only : Flag<["-"], "fdriver-only">, Flags<[NoXarchOption]>,
   Visibility<[ClangOption, CLOption, DXCOption]>,
@@ -4232,7 +4235,7 @@ defm virtual_function_elimination : BoolFOption<"virtual-function-elimination",
   NegFlag<SetFalse>, BothFlags<[], [ClangOption, CLOption]>>;
 
 def fwrapv : Flag<["-"], "fwrapv">, Group<f_Group>,
-  Visibility<[ClangOption, CC1Option]>,
+  Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
   HelpText<"Treat signed integer overflow as two's complement">;
 def fwritable_strings : Flag<["-"], "fwritable-strings">, Group<f_Group>,
   Visibility<[ClangOption, CC1Option]>,
diff --git a/clang/lib/Driver/ToolChains/Flang.cpp b/clang/lib/Driver/ToolChains/Flang.cpp
index 98350690f8d20e..1865fd57a2d893 100644
--- a/clang/lib/Driver/ToolChains/Flang.cpp
+++ b/clang/lib/Driver/ToolChains/Flang.cpp
@@ -866,6 +866,17 @@ void Flang::ConstructJob(Compilation &C, const JobAction &JA,
     }
   }
 
+  // -fno-strict-overflow implies -fwrapv if it isn't disabled, but
+  // -fstrict-overflow won't turn off an explicitly enabled -fwrapv.
+  if (Arg *A = Args.getLastArg(options::OPT_fwrapv, options::OPT_fno_wrapv)) {
+    if (A->getOption().matches(options::OPT_fwrapv))
+      CmdArgs.push_back("-fwrapv");
+  } else if (Arg *A = Args.getLastArg(options::OPT_fstrict_overflow,
+                                      options::OPT_fno_strict_overflow)) {
+    if (A->getOption().matches(options::OPT_fno_strict_overflow))
+      CmdArgs.push_back("-fwrapv");
+  }
+
   assert((Output.isFilename() || Output.isNothing()) && "Invalid output.");
   if (Output.isFilename()) {
     CmdArgs.push_back("-o");
diff --git a/flang/include/flang/Common/LangOptions.def b/flang/include/flang/Common/LangOptions.def
index d3e1e972d1519f..1bfdba9cc2c1c7 100644
--- a/flang/include/flang/Common/LangOptions.def
+++ b/flang/include/flang/Common/LangOptions.def
@@ -20,6 +20,8 @@ LANGOPT(Name, Bits, Default)
 #endif
 
 ENUM_LANGOPT(FPContractMode, FPModeKind, 2, FPM_Fast) ///< FP Contract Mode (off/fast)
+/// signed integer overflow handling
+ENUM_LANGOPT(SignedOverflowBehavior, SignedOverflowBehaviorTy, 1, SOB_Undefined)
 
 /// Indicate a build without the standard GPU libraries.
 LANGOPT(NoGPULib  , 1, false)
diff --git a/flang/include/flang/Common/LangOptions.h b/flang/include/flang/Common/LangOptions.h
index 52a45047deb0e2..83f25cfbe26142 100644
--- a/flang/include/flang/Common/LangOptions.h
+++ b/flang/include/flang/Common/LangOptions.h
@@ -27,6 +27,14 @@ namespace Fortran::common {
 class LangOptionsBase {
 
 public:
+  enum SignedOverflowBehaviorTy {
+    // -fno-wrapv (default behavior in Flang)
+    SOB_Undefined,
+
+    // -fwrapv
+    SOB_Defined,
+  };
+
   enum FPModeKind {
     // Do not fuse FP ops
     FPM_Off,
diff --git a/flang/include/flang/Lower/LoweringOptions.def b/flang/include/flang/Lower/LoweringOptions.def
index d3f17c3f939c16..231de533fbd30a 100644
--- a/flang/include/flang/Lower/LoweringOptions.def
+++ b/flang/include/flang/Lower/LoweringOptions.def
@@ -35,9 +35,8 @@ ENUM_LOWERINGOPT(NoPPCNativeVecElemOrder, unsigned, 1, 0)
 ENUM_LOWERINGOPT(Underscoring, unsigned, 1, 1)
 
 /// If true, assume the behavior of integer overflow is defined
-/// (i.e. wraps around as two's complement). On by default.
-/// TODO: make the default off
-ENUM_LOWERINGOPT(IntegerWrapAround, unsigned, 1, 1)
+/// (i.e. wraps around as two's complement). Off by default.
+ENUM_LOWERINGOPT(IntegerWrapAround, unsigned, 1, 0)
 
 /// If true, add nsw flags to loop variable increments.
 /// Off by default.
diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index 2154b9ab2fbf47..c8160a4236b466 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -1109,6 +1109,24 @@ static bool parseOpenMPArgs(CompilerInvocation &res, llvm::opt::ArgList &args,
   return diags.getNumErrors() == numErrorsBefore;
 }
 
+/// Parses signed integer overflow options and populates the
+/// CompilerInvocation accordingly.
+/// Returns false if new errors are generated.
+///
+/// \param [out] invoc Stores the processed arguments
+/// \param [in] args The compiler invocation arguments to parse
+/// \param [out] diags DiagnosticsEngine to report erros with
+static bool parseIntegerOverflowArgs(CompilerInvocation &invoc,
+                                     llvm::opt::ArgList &args,
+                                     clang::DiagnosticsEngine &diags) {
+  Fortran::common::LangOptions &opts = invoc.getLangOpts();
+
+  if (args.getLastArg(clang::driver::options::OPT_fwrapv))
+    opts.setSignedOverflowBehavior(Fortran::common::LangOptions::SOB_Defined);
+
+  return true;
+}
+
 /// Parses all floating point related arguments and populates the
 /// CompilerInvocation accordingly.
 /// Returns false if new errors are generated.
@@ -1249,6 +1267,18 @@ static bool parseLinkerOptionsArgs(CompilerInvocation &invoc,
   return true;
 }
 
+static bool parseLangOptionsArgs(CompilerInvocation &invoc,
+                                 llvm::opt::ArgList &args,
+                                 clang::DiagnosticsEngine &diags) {
+  bool success = true;
+
+  success &= parseIntegerOverflowArgs(invoc, args, diags);
+  success &= parseFloatingPointArgs(invoc, args, diags);
+  success &= parseVScaleArgs(invoc, args, diags);
+
+  return success;
+}
+
 bool CompilerInvocation::createFromArgs(
     CompilerInvocation &invoc, llvm::ArrayRef<const char *> commandLineArgs,
     clang::DiagnosticsEngine &diags, const char *argv0) {
@@ -1357,9 +1387,7 @@ bool CompilerInvocation::createFromArgs(
   invoc.frontendOpts.mlirArgs =
       args.getAllArgValues(clang::driver::options::OPT_mmlir);
 
-  success &= parseFloatingPointArgs(invoc, args, diags);
-
-  success &= parseVScaleArgs(invoc, args, diags);
+  success &= parseLangOptionsArgs(invoc, args, diags);
 
   success &= parseLinkerOptionsArgs(invoc, args, diags);
 
@@ -1571,6 +1599,8 @@ void CompilerInvocation::setLoweringOptions() {
   loweringOpts.setUnderscoring(codegenOpts.Underscoring);
 
   const Fortran::common::LangOptions &langOptions = getLangOpts();
+  loweringOpts.setIntegerWrapAround(langOptions.getSignedOverflowBehavior() ==
+                                    Fortran::common::LangOptions::SOB_Defined);
   Fortran::common::MathOptionsBase &mathOpts = loweringOpts.getMathOptions();
   // TODO: when LangOptions are finalized, we can represent
   //       the math related options using Fortran::commmon::MathOptionsBase,
diff --git a/flang/test/Driver/frontend-forwarding.f90 b/flang/test/Driver/frontend-forwarding.f90
index 35adb47b56861e..382c1aa5d350b7 100644
--- a/flang/test/Driver/frontend-forwarding.f90
+++ b/flang/test/Driver/frontend-forwarding.f90
@@ -14,6 +14,7 @@
 ! RUN:     -fno-signed-zeros \
 ! RUN:     -fassociative-math \
 ! RUN:     -freciprocal-math \
+! RUN:     -fno-strict-overflow \
 ! RUN:     -fomit-frame-pointer \
 ! RUN:     -fpass-plugin=Bye%pluginext \
 ! RUN:     -fversion-loops-for-stride \
@@ -63,4 +64,5 @@
 ! CHECK: "-Rpass=inline"
 ! CHECK: "-mframe-pointer=none"
 ! CHECK: "-mllvm" "-print-before-all"
+! CHECK: "-fwrapv"
 ! CHECK: "-save-temps=obj"
diff --git a/flang/test/Driver/integer-overflow.f90 b/flang/test/Driver/integer-overflow.f90
new file mode 100644
index 00000000000000..2cfb36527a30ad
--- /dev/null
+++ b/flang/test/Driver/integer-overflow.f90
@@ -0,0 +1,10 @@
+! Test for correct forwarding of integer overflow flags from the compiler driver
+! to the frontend driver
+
+! RUN: %flang -### -fno-strict-overflow %s 2>&1 | FileCheck %s --check-prefixes CHECK,INDUCED
+! RUN: %flang -### -fstrict-overflow %s 2>&1 | FileCheck %s
+! RUN: %flang -### -fno-wrapv %s 2>&1 | FileCheck %s
+! RUN: %flang -### -fno-wrapv -fno-strict-overflow %s 2>&1 | FileCheck %s
+
+! CHECK-NOT: "-fno-wrapv"
+! INDUCED: "-fwrapv"

tarunprabhu · 2024-10-03T13:44:07Z

clang/lib/Driver/ToolChains/Flang.cpp

+  // -fno-strict-overflow implies -fwrapv if it isn't disabled, but
+  // -fstrict-overflow won't turn off an explicitly enabled -fwrapv.
+  if (Arg *A = Args.getLastArg(options::OPT_fwrapv, options::OPT_fno_wrapv)) {
+    if (A->getOption().matches(options::OPT_fwrapv))
+      CmdArgs.push_back("-fwrapv");
+  } else if (Arg *A = Args.getLastArg(options::OPT_fstrict_overflow,
+                                      options::OPT_fno_strict_overflow)) {
+    if (A->getOption().matches(options::OPT_fno_strict_overflow))
+      CmdArgs.push_back("-fwrapv");
+  }
+


If this code is exactly the same as it is in clang, it would be better if it is shared. In clang/lib/Driver/ToolChains/CommonArgs.cpp, see handleColorDiagnosticsArgs for a case of common argument handling functionality between clang and flang. This was done in #109210

Thank you for showing me a better way.
I created a function renderIntegerOverflowOptions to handle common options between clang and flang. However, I'm not sure the name of the function is appropriate because there are other related options handled only by clang (e.g. -ftrapv).

Perhaps the function could be named renderCommonIntegerOverflowOptions which suggests that it does not handle all overflow options?

That sounds good. I fixed it. Thank you.

tarunprabhu · 2024-10-03T13:45:13Z

flang/test/Driver/integer-overflow.f90

+! Test for correct forwarding of integer overflow flags from the compiler driver
+! to the frontend driver
+
+! RUN: %flang -### -fno-strict-overflow %s 2>&1 | FileCheck %s --check-prefixes CHECK,INDUCED


Do we need both the CHECK and INDUCED here?

As you mentioned, the check for CHECK is redundant. I removed it.

MaskRay · 2024-10-05T05:55:39Z

clang/lib/Driver/ToolChains/Clang.cpp

-    if (A->getOption().matches(options::OPT_fno_strict_overflow))
-      CmdArgs.push_back("-fwrapv");
-  }
+  // handle -f[no-]wrapv and -f[no-]strict-overflow, which are used by both


// Handle ...

Capitalization and adding a trailing period.

Thank you for pointing it out. I fixed it.

MaskRay · 2024-10-05T05:56:41Z

flang/include/flang/Common/LangOptions.h

@@ -27,6 +27,14 @@ namespace Fortran::common {
 class LangOptionsBase {

 public:
+  enum SignedOverflowBehaviorTy {
+    // -fno-wrapv (default behavior in Flang)
+    SOB_Undefined,


unused? Not sure that this definition is useful

This is used as the default value of a LangOption SignedOverflowBehavior. If the behavior is not defined, nsw could be added to some operations such as add.
FWIW, this implementation is simliar to that of Clang.

tarunprabhu

Thank you for the changes, Minato san. LGTM.

yus3710-fj · 2024-10-15T00:10:18Z

Gentle ping @MaskRay.

tblah

This looks good to me, thanks!

MaskRay

clangDriver part LG.

yus3710-fj · 2024-10-18T00:02:10Z

Thank you all for the review! I'll merge this after rebasing.

…ow in the frontend This patch introduces the options for integer overflow flags into Flang.

yus3710-fj · 2024-10-18T05:48:50Z

CI failed due to ClangdTests/25/79 (DynamicIndexIncludeInsertion in CodeCompleteTests.cpp?). It's weird because there is no functional change on clang (and clangd). In addition, I can't reproduce this on my machine.
I'll try re-running CI with an empty commit.

yus3710-fj · 2024-10-18T07:29:11Z

CI failed again, but the test mentioned above was passed this time. So, I think I can merge this.

…ow in the frontend (llvm#110061) This patch introduces the options for integer overflow flags into Flang. The behavior is similar to that of Clang.

yus3710-fj linked an issue Sep 26, 2024 that may be closed by this pull request

[Flang] TSVC s243: some nsw flags for address calculations will help vectorization #78934

Closed

yus3710-fj force-pushed the options-for-overflow branch from d3a02bc to aea2cfa Compare October 3, 2024 03:51

yus3710-fj marked this pull request as ready for review October 3, 2024 04:15

llvmbot added clang Clang issues not falling into any other category clang:driver 'clang' and 'clang++' user-facing binaries. Not 'clang-cl' flang:driver flang Flang issues not falling into any other category flang:fir-hlfir labels Oct 3, 2024

yus3710-fj requested review from tblah, tarunprabhu and jeanPerier October 3, 2024 04:16

tarunprabhu requested changes Oct 3, 2024

View reviewed changes

yus3710-fj mentioned this pull request Oct 4, 2024

[Flang] TSVC s243: some nsw flags for address calculations will help vectorization #78934

Closed

yus3710-fj requested review from tarunprabhu and MaskRay October 4, 2024 07:37

MaskRay reviewed Oct 5, 2024

View reviewed changes

tarunprabhu approved these changes Oct 7, 2024

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yus3710-fj requested a review from MaskRay October 8, 2024 03:09

tblah approved these changes Oct 15, 2024

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MaskRay approved these changes Oct 17, 2024

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[flang][Driver] Add support for -f[no-]wrapv and -f[no]-strict-overfl…

6215099

…ow in the frontend This patch introduces the options for integer overflow flags into Flang.

yus3710-fj force-pushed the options-for-overflow branch from be8ff0f to 6215099 Compare October 18, 2024 01:40

empty commit for CI

2a41e6f

yus3710-fj merged commit 9698e57 into llvm:main Oct 18, 2024
6 of 8 checks passed

yus3710-fj deleted the options-for-overflow branch October 18, 2024 07:30

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[flang][Driver] Add support for -f[no-]wrapv and -f[no]-strict-overflow in the frontend #110061

[flang][Driver] Add support for -f[no-]wrapv and -f[no]-strict-overflow in the frontend #110061

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[flang][Driver] Add support for -f[no-]wrapv and -f[no]-strict-overflow in the frontend #110061

[flang][Driver] Add support for -f[no-]wrapv and -f[no]-strict-overflow in the frontend #110061

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