[flang-commits] [flang] 62d4cc8 - [flang] Modifications to ieee_support_standard (#128895)

via flang-commits flang-commits at lists.llvm.org
Thu Feb 27 11:57:14 PST 2025


Author: vdonaldson
Date: 2025-02-27T14:57:10-05:00
New Revision: 62d4cc811ae132c722a2146ddb246c3710b57a93

URL: https://github.com/llvm/llvm-project/commit/62d4cc811ae132c722a2146ddb246c3710b57a93
DIFF: https://github.com/llvm/llvm-project/commit/62d4cc811ae132c722a2146ddb246c3710b57a93.diff

LOG: [flang] Modifications to ieee_support_standard (#128895)

Some Arm processors support exception halting control and some do not.
An Arm executable will run on either type of processor, so it is
effectively unknown at compile time whether or not this support will be
available. ieee_support_halting is therefore implemented with a runtime
check.

The result of a call to ieee_support_standard depends in part on support
for halting control. Update the ieee_support_standard implementation to
check for support for halting control at runtime.

Added: 
    

Modified: 
    flang/docs/Extensions.md
    flang/include/flang/Optimizer/Builder/IntrinsicCall.h
    flang/lib/Evaluate/fold-logical.cpp
    flang/lib/Evaluate/intrinsics.cpp
    flang/lib/Optimizer/Builder/IntrinsicCall.cpp

Removed: 
    


################################################################################
diff  --git a/flang/docs/Extensions.md b/flang/docs/Extensions.md
index 1dc0b65271b27..e70f40306c4e1 100644
--- a/flang/docs/Extensions.md
+++ b/flang/docs/Extensions.md
@@ -150,13 +150,15 @@ end
   have this capability. An Arm executable will run on either type of
   processor, so it is effectively unknown at compile time whether or
   not this support will be available at runtime. The standard requires
-  that a call to intrinsic module procedure `IEEE_SUPPORT_HALTING` with
+  that a call to intrinsic module procedure `ieee_support_halting` with
   a constant argument has a compile time constant result in `constant
   expression` and `specification expression` contexts. In compilations
   where this information is not known at compile time, f18 generates code
   to determine the absence or presence of this capability at runtime.
-  A call to `IEEE_SUPPORT_HALTING` in contexts that the standard requires
-  to be constant will generate a compilation error.
+  A call to `ieee_support_halting` in contexts that the standard requires
+  to be constant will generate a compilation error. `ieee_support_standard`
+  depends in part on `ieee_support_halting`, so this also applies to
+  `ieee_support_standard` calls.
 
 ## Extensions, deletions, and legacy features supported by default
 

diff  --git a/flang/include/flang/Optimizer/Builder/IntrinsicCall.h b/flang/include/flang/Optimizer/Builder/IntrinsicCall.h
index f5971610694f0..c82e5265970c5 100644
--- a/flang/include/flang/Optimizer/Builder/IntrinsicCall.h
+++ b/flang/include/flang/Optimizer/Builder/IntrinsicCall.h
@@ -313,7 +313,10 @@ struct IntrinsicLibrary {
                                         llvm::ArrayRef<fir::ExtendedValue>);
   fir::ExtendedValue genIeeeSupportHalting(mlir::Type,
                                            llvm::ArrayRef<fir::ExtendedValue>);
-  mlir::Value genIeeeSupportRounding(mlir::Type, llvm::ArrayRef<mlir::Value>);
+  fir::ExtendedValue genIeeeSupportRounding(mlir::Type,
+                                            llvm::ArrayRef<fir::ExtendedValue>);
+  fir::ExtendedValue genIeeeSupportStandard(mlir::Type,
+                                            llvm::ArrayRef<fir::ExtendedValue>);
   template <mlir::arith::CmpIPredicate pred>
   mlir::Value genIeeeTypeCompare(mlir::Type, llvm::ArrayRef<mlir::Value>);
   mlir::Value genIeeeUnordered(mlir::Type, llvm::ArrayRef<mlir::Value>);

diff  --git a/flang/lib/Evaluate/fold-logical.cpp b/flang/lib/Evaluate/fold-logical.cpp
index e3ec1a1af8881..77f8e0f616878 100644
--- a/flang/lib/Evaluate/fold-logical.cpp
+++ b/flang/lib/Evaluate/fold-logical.cpp
@@ -882,7 +882,7 @@ Expr<Type<TypeCategory::Logical, KIND>> FoldIntrinsicFunction(
         IeeeFeature::Flags)};
   } else if (name == "__builtin_ieee_support_halting") {
     if (!context.targetCharacteristics()
-             .haltingSupportIsUnknownAtCompileTime()) {
+            .haltingSupportIsUnknownAtCompileTime()) {
       return Expr<T>{context.targetCharacteristics().ieeeFeatures().test(
           IeeeFeature::Halting)};
     }
@@ -906,8 +906,12 @@ Expr<Type<TypeCategory::Logical, KIND>> FoldIntrinsicFunction(
     return Expr<T>{
         context.targetCharacteristics().ieeeFeatures().test(IeeeFeature::Sqrt)};
   } else if (name == "__builtin_ieee_support_standard") {
-    return Expr<T>{context.targetCharacteristics().ieeeFeatures().test(
-        IeeeFeature::Standard)};
+    // ieee_support_standard depends in part on ieee_support_halting.
+    if (!context.targetCharacteristics()
+            .haltingSupportIsUnknownAtCompileTime()) {
+      return Expr<T>{context.targetCharacteristics().ieeeFeatures().test(
+          IeeeFeature::Standard)};
+    }
   } else if (name == "__builtin_ieee_support_subnormal") {
     return Expr<T>{context.targetCharacteristics().ieeeFeatures().test(
         IeeeFeature::Subnormal)};

diff  --git a/flang/lib/Evaluate/intrinsics.cpp b/flang/lib/Evaluate/intrinsics.cpp
index 5c9527cec2f69..6d8f19388d8b7 100644
--- a/flang/lib/Evaluate/intrinsics.cpp
+++ b/flang/lib/Evaluate/intrinsics.cpp
@@ -1022,45 +1022,35 @@ static const IntrinsicInterface genericIntrinsicFunction[]{
     {"__builtin_ieee_next_up", {{"x", SameReal}}, SameReal},
     {"__builtin_ieee_real", {{"a", AnyIntOrReal}, DefaultingKIND}, KINDReal},
     {"__builtin_ieee_support_datatype",
-        {{"x", AnyReal, Rank::elemental, Optionality::optional}},
-        DefaultLogical},
+        {{"x", AnyReal, Rank::known, Optionality::optional}}, DefaultLogical},
     {"__builtin_ieee_support_denormal",
-        {{"x", AnyReal, Rank::elemental, Optionality::optional}},
-        DefaultLogical},
+        {{"x", AnyReal, Rank::known, Optionality::optional}}, DefaultLogical},
     {"__builtin_ieee_support_divide",
-        {{"x", AnyReal, Rank::elemental, Optionality::optional}},
-        DefaultLogical},
+        {{"x", AnyReal, Rank::known, Optionality::optional}}, DefaultLogical},
     {"__builtin_ieee_support_flag",
         {{"flag", IeeeFlagType, Rank::scalar},
-            {"x", AnyReal, Rank::elemental, Optionality::optional}},
+            {"x", AnyReal, Rank::known, Optionality::optional}},
         DefaultLogical},
     {"__builtin_ieee_support_halting", {{"flag", IeeeFlagType, Rank::scalar}},
         DefaultLogical},
     {"__builtin_ieee_support_inf",
-        {{"x", AnyReal, Rank::elemental, Optionality::optional}},
-        DefaultLogical},
+        {{"x", AnyReal, Rank::known, Optionality::optional}}, DefaultLogical},
     {"__builtin_ieee_support_io",
-        {{"x", AnyReal, Rank::elemental, Optionality::optional}},
-        DefaultLogical},
+        {{"x", AnyReal, Rank::known, Optionality::optional}}, DefaultLogical},
     {"__builtin_ieee_support_nan",
-        {{"x", AnyReal, Rank::elemental, Optionality::optional}},
-        DefaultLogical},
+        {{"x", AnyReal, Rank::known, Optionality::optional}}, DefaultLogical},
     {"__builtin_ieee_support_rounding",
         {{"round_value", IeeeRoundType, Rank::scalar},
-            {"x", AnyReal, Rank::elemental, Optionality::optional}},
+            {"x", AnyReal, Rank::known, Optionality::optional}},
         DefaultLogical},
     {"__builtin_ieee_support_sqrt",
-        {{"x", AnyReal, Rank::elemental, Optionality::optional}},
-        DefaultLogical},
+        {{"x", AnyReal, Rank::known, Optionality::optional}}, DefaultLogical},
     {"__builtin_ieee_support_standard",
-        {{"x", AnyReal, Rank::elemental, Optionality::optional}},
-        DefaultLogical},
+        {{"x", AnyReal, Rank::known, Optionality::optional}}, DefaultLogical},
     {"__builtin_ieee_support_subnormal",
-        {{"x", AnyReal, Rank::elemental, Optionality::optional}},
-        DefaultLogical},
+        {{"x", AnyReal, Rank::known, Optionality::optional}}, DefaultLogical},
     {"__builtin_ieee_support_underflow_control",
-        {{"x", AnyReal, Rank::elemental, Optionality::optional}},
-        DefaultLogical},
+        {{"x", AnyReal, Rank::known, Optionality::optional}}, DefaultLogical},
     {"__builtin_numeric_storage_size", {}, DefaultInt},
 };
 

diff  --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
index ecd79c45bdb13..c52b0cbaf2019 100644
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -456,8 +456,18 @@ static constexpr IntrinsicHandler handlers[]{
      &I::genIeeeSupportFlag,
      {{{"flag", asValue}, {"x", asInquired, handleDynamicOptional}}},
      /*isElemental=*/false},
-    {"ieee_support_halting", &I::genIeeeSupportHalting},
-    {"ieee_support_rounding", &I::genIeeeSupportRounding},
+    {"ieee_support_halting",
+     &I::genIeeeSupportHalting,
+     {{{"flag", asValue}}},
+     /*isElemental=*/false},
+    {"ieee_support_rounding",
+     &I::genIeeeSupportRounding,
+     {{{"round_value", asValue}, {"x", asInquired, handleDynamicOptional}}},
+     /*isElemental=*/false},
+    {"ieee_support_standard",
+     &I::genIeeeSupportStandard,
+     {{{"flag", asValue}, {"x", asInquired, handleDynamicOptional}}},
+     /*isElemental=*/false},
     {"ieee_unordered", &I::genIeeeUnordered},
     {"ieee_value", &I::genIeeeValue},
     {"ieor", &I::genIeor},
@@ -5629,7 +5639,7 @@ IntrinsicLibrary::genIeeeSupportFlag(mlir::Type resultType,
   // is therefore ignored. Standard flags are all supported. The nonstandard
   // DENORM extension is not supported, at least for now.
   assert(args.size() == 1 || args.size() == 2);
-  auto [fieldRef, fieldTy] = getFieldRef(builder, loc, fir::getBase(args[0]));
+  auto [fieldRef, fieldTy] = getFieldRef(builder, loc, getBase(args[0]));
   mlir::Value flag = builder.create<fir::LoadOp>(loc, fieldRef);
   mlir::Value mask = builder.createIntegerConstant( // values are powers of 2
       loc, fieldTy,
@@ -5661,9 +5671,8 @@ fir::ExtendedValue IntrinsicLibrary::genIeeeSupportHalting(
 }
 
 // IEEE_SUPPORT_ROUNDING
-mlir::Value
-IntrinsicLibrary::genIeeeSupportRounding(mlir::Type resultType,
-                                         llvm::ArrayRef<mlir::Value> args) {
+fir::ExtendedValue IntrinsicLibrary::genIeeeSupportRounding(
+    mlir::Type resultType, llvm::ArrayRef<fir::ExtendedValue> args) {
   // Check if floating point rounding mode ROUND_VALUE is supported.
   // Rounding is supported either for all type kinds or none.
   // An optional X kind argument is therefore ignored.
@@ -5674,7 +5683,7 @@ IntrinsicLibrary::genIeeeSupportRounding(mlir::Type resultType,
   //  3 - toward negative infinity [supported]
   //  4 - to nearest, ties away from zero [not supported]
   assert(args.size() == 1 || args.size() == 2);
-  auto [fieldRef, fieldTy] = getFieldRef(builder, loc, args[0]);
+  auto [fieldRef, fieldTy] = getFieldRef(builder, loc, getBase(args[0]));
   mlir::Value mode = builder.create<fir::LoadOp>(loc, fieldRef);
   mlir::Value lbOk = builder.create<mlir::arith::CmpIOp>(
       loc, mlir::arith::CmpIPredicate::sge, mode,
@@ -5687,6 +5696,19 @@ IntrinsicLibrary::genIeeeSupportRounding(mlir::Type resultType,
       loc, resultType, builder.create<mlir::arith::AndIOp>(loc, lbOk, ubOk));
 }
 
+// IEEE_SUPPORT_STANDARD
+fir::ExtendedValue IntrinsicLibrary::genIeeeSupportStandard(
+    mlir::Type resultType, llvm::ArrayRef<fir::ExtendedValue> args) {
+  // Check if IEEE standard support is available, which reduces to checking
+  // if halting control is supported, as that is the only support component
+  // that may not be available.
+  assert(args.size() <= 1);
+  mlir::Value nearest = builder.createIntegerConstant(
+      loc, builder.getIntegerType(32), _FORTRAN_RUNTIME_IEEE_NEAREST);
+  return builder.createConvert(
+      loc, resultType, fir::runtime::genSupportHalting(builder, loc, nearest));
+}
+
 // IEEE_UNORDERED
 mlir::Value
 IntrinsicLibrary::genIeeeUnordered(mlir::Type resultType,


        


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