[PATCH] D137986: [Clang][CodeGen][AIX] Map __builtin_frexpl, __builtin_ldexpl, and __builtin_modfl to 'double' version lib calls in 64-bit 'long double' mode

[Xing Xue via Phabricator via cfe-commits]

xingxue created this revision.
xingxue added reviewers: rjmccall, hubert.reinterpretcast, daltenty, cebowleratibm.
xingxue added a project: LLVM.
Herald added a project: All.
xingxue requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

AIX library functions `frexpl()`, `ldexpl()`, and `modfl()` are for 128-bit `long double`. Other `*l()` functions, e.g., `acosl()`, are for 64-bit `long double`. The AIX Clang compiler currently maps builtin functions `__builtin_frexpl()`, `__builtin_ldexpl()`, and `__builtin_modfl()` to `frexpl()`, `ldexpl()`, and `modfl()` in 64-bit `long double` mode which results in seg-faults or incorrect return values. This patch changes to map `__builtin_frexpl()`, `__builtin_ldexpl()`, and `__builtin_modfl()` to `double` version lib functions `frexp()`, `ldexp()` and `modf()` in 64-bit `long double` mode. The following is from AIX <math.h>.

  /*
   * frexpl(), ldexpl(), and modfl() have preexisting shared versions which are
   * 128-bit only.  64-bit versions must be made available for C99 for the
   * default 64-bit long double.  These cannot simply be macros because the
   * actual routines will be the incorrect form in 64-bit mode if the user
   * forces the actual routines to be used through undef or macro suppression
   * per the standard.
   */
  #if defined(_ISOC99_SOURCE) && !defined(__LONGDOUBLE128)
  static long double _NOTHROW(frexpl, (long double __x, int *__i))
  {
       return (long double) frexp((double) __x, __i);
  }
  
  static long double _NOTHROW(ldexpl, (long double __x, int __i))
  {
       return (long double) ldexp((double) __x, __i);
  }
  
  #ifndef __MODFL
  static long double _NOTHROW(modfl, (long double __x, long double *__y))
  {
       return (long double) modf((double) __x, (double *) __y);
  }
  #endif
  #endif


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D137986

Files:
  clang/lib/CodeGen/CGBuiltin.cpp
  clang/test/CodeGen/aix-builtin-mapping.c


Index: clang/test/CodeGen/aix-builtin-mapping.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/aix-builtin-mapping.c
@@ -0,0 +1,22 @@
+// AIX library functions frexpl, ldexpl, and modfl are for 128-bit
+// 'long double'. Check that the compiler generates calls to the 'double'
+// versions for correspoding builtin functions in 64-bit 'long double' mode.
+
+// RUN: %clang_cc1 -triple powerpc-ibm-aix -mlong-double-64 -S -o - %s | FileCheck %s -check-prefix=CHECK
+// RUN: %clang_cc1 -triple powerpc64-ibm-aix -mlong-double-64 -S -o - %s | FileCheck %s -check-prefix=CHECK
+
+int main()
+{
+  int DummyInt;
+  long double DummyLongDouble;
+  long double returnValue;
+
+  returnValue = __builtin_modfl(1.0L, &DummyLongDouble);
+  returnValue = __builtin_frexpl(0.0L, &DummyInt);
+  returnValue = __builtin_ldexpl(1.0L, 1);
+}
+
+// CHECK:  bl .modf[PR]
+// CHECK:  bl .frexp[PR]
+// CHECK:  bl .ldexp[PR]
+
Index: clang/lib/CodeGen/CGBuiltin.cpp
===================================================================
--- clang/lib/CodeGen/CGBuiltin.cpp
+++ clang/lib/CodeGen/CGBuiltin.cpp
@@ -106,6 +106,15 @@
       {Builtin::BI__builtin_nexttowardf128, "__nexttowardieee128"},
   };
 
+  // The AIX library functions frexpl, ldexpl, and modfl are for 128-bit
+  // 'long double'. Map to the 'double' versions if it is 64-bit 'long
+  // double' mode.
+  static SmallDenseMap<unsigned, StringRef, 4> AIXLongDoubleBuiltins{
+      {Builtin::BI__builtin_frexpl, "frexp"},
+      {Builtin::BI__builtin_ldexpl, "ldexp"},
+      {Builtin::BI__builtin_modfl, "modf"},
+  };
+
   // If the builtin has been declared explicitly with an assembler label,
   // use the mangled name. This differs from the plain label on platforms
   // that prefix labels.
@@ -118,6 +127,12 @@
         &getTarget().getLongDoubleFormat() == &llvm::APFloat::IEEEquad() &&
         F128Builtins.find(BuiltinID) != F128Builtins.end())
       Name = F128Builtins[BuiltinID];
+    else if (getTriple().isOSAIX() &&
+             &getTarget().getLongDoubleFormat() ==
+                 &llvm::APFloat::IEEEdouble() &&
+             AIXLongDoubleBuiltins.find(BuiltinID) !=
+                 AIXLongDoubleBuiltins.end())
+      Name = AIXLongDoubleBuiltins[BuiltinID];
     else
       Name = Context.BuiltinInfo.getName(BuiltinID) + 10;
   }


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D137986.475206.patch
Type: text/x-patch
Size: 2365 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20221114/521b7f2d/attachment-0001.bin>