Add a new target-independent code generator flag.

llvm-svn: 19567

llvm/include/llvm/Target/TargetOptions.h

@@ -25,6 +25,15 @@ namespace llvm {
   /// specified on the command line.  If the target supports the frame pointer
   /// elimination optimization, this option should disable it.
   extern bool NoFramePointerElim;
+
+  /// NoExcessFPPrecision - This flag is enabled when the
+  /// -disable-excess-fp-precision flag is specified on the command line.  When
+  /// this flag is off (the default), the code generator is allowed to produce
+  /// results that are "more precise" than IEEE allows.  This includes use of
+  /// FMA-like operations and use of the X86 FP registers without rounding all
+  /// over the place.
+  extern bool NoExcessFPPrecision;
+
 } // End llvm namespace
 
 #endif

llvm/lib/Target/TargetMachine.cpp

@@ -24,6 +24,7 @@ using namespace llvm;
 namespace llvm {
   bool PrintMachineCode;
   bool NoFramePointerElim;
+  bool NoExcessFPPrecision;
 };
 namespace {
   cl::opt<bool, true> PrintCode("print-machineinstrs",
@@ -35,6 +36,11 @@ namespace {
                   cl::desc("Disable frame pointer elimination optimization"),
                   cl::location(NoFramePointerElim),
                   cl::init(false));
+  cl::opt<bool, true>
+  DisableExcessPrecision("disable-excess-fp-precision",
+                         cl::desc("Disable optimizations that may increase FP precision"),
+                         cl::location(NoExcessFPPrecision),
+                         cl::init(false));
 };
 
 //---------------------------------------------------------------------------