// FIXME: Currently, this is only flagged for Cortex-A8. It may be true for
// others as well. We should do more benchmarking and confirm one way or
// the other.
-def FeatureHasSlowVMLx : SubtargetFeature<"vmlx", "SlowVMLx", "true",
- "Disable VFP MAC instructions">;
-// Some processors benefit from using NEON instructions for scalar
-// single-precision FP operations.
-def FeatureNEONForFP : SubtargetFeature<"neonfp", "UseNEONForSinglePrecisionFP",
- "true",
- "Use NEON for single precision FP">;
-
+def HasSlowVMLx : SubtargetFeature<"vmlx", "SlowVMLx", "true",
+ "Disable VFP MAC instructions">;
//===----------------------------------------------------------------------===//
// ARM Processors supported.
// V7 Processors.
def : Processor<"cortex-a8", CortexA8Itineraries,
- [ArchV7A, FeatureThumb2, FeatureNEON, FeatureHasSlowVMLx,
- FeatureNEONForFP]>;
+ [ArchV7A, FeatureThumb2, FeatureNEON, HasSlowVMLx]>;
def : ProcNoItin<"cortex-a9", [ArchV7A, FeatureThumb2, FeatureNEON]>;
//===----------------------------------------------------------------------===//
static cl::opt<bool>
ReserveR9("arm-reserve-r9", cl::Hidden,
cl::desc("Reserve R9, making it unavailable as GPR"));
+static cl::opt<bool>
+UseNEONFP("arm-use-neon-fp",
+ cl::desc("Use NEON for single-precision FP"),
+ cl::init(false), cl::Hidden);
static cl::opt<bool>
UseMOVT("arm-use-movt",
bool isT)
: ARMArchVersion(V4)
, ARMFPUType(None)
- , UseNEONForSinglePrecisionFP(false)
+ , UseNEONForSinglePrecisionFP(UseNEONFP)
, SlowVMLx(false)
, IsThumb(isT)
, ThumbMode(Thumb1)
if (!isThumb() || hasThumb2())
PostRAScheduler = true;
+
+ // Set CPU specific features.
+ if (CPUString == "cortex-a8") {
+ // On Cortex-a8, it's faster to perform some single-precision FP
+ // operations with NEON instructions.
+ if (UseNEONFP.getPosition() == 0)
+ UseNEONForSinglePrecisionFP = true;
+ }
}
/// GVIsIndirectSymbol - true if the GV will be accessed via an indirect symbol.