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-rw-r--r--lib/Target/ARM/ARM.td11
1 files changed, 10 insertions, 1 deletions
diff --git a/lib/Target/ARM/ARM.td b/lib/Target/ARM/ARM.td
index e690e18672..133af31a38 100644
--- a/lib/Target/ARM/ARM.td
+++ b/lib/Target/ARM/ARM.td
@@ -67,6 +67,14 @@ def FeatureNEONForFP : SubtargetFeature<"neonfp", "UseNEONForSinglePrecisionFP",
def FeaturePref32BitThumb : SubtargetFeature<"32bit", "Pref32BitThumb", "true",
"Prefer 32-bit Thumb instrs">;
+/// Some instructions update CPSR partially, which can add false dependency for
+/// out-of-order implementation, e.g. Cortex-A9, unless each individual bit is
+/// mapped to a separate physical register. Avoid partial CPSR update for these
+/// processors.
+def FeatureAvoidPartialCPSR : SubtargetFeature<"avoid-partial-cpsr",
+ "AvoidCPSRPartialUpdate", "true",
+ "Avoid CPSR partial update for OOO execution">;
+
// Multiprocessing extension.
def FeatureMP : SubtargetFeature<"mp", "HasMPExtension", "true",
"Supports Multiprocessing extension">;
@@ -111,7 +119,8 @@ def ProcA8 : SubtargetFeature<"a8", "ARMProcFamily", "CortexA8",
def ProcA9 : SubtargetFeature<"a9", "ARMProcFamily", "CortexA9",
"Cortex-A9 ARM processors",
[FeatureHasSlowFPVMLx, FeatureVMLxForwarding,
- FeatureT2XtPk, FeatureFP16]>;
+ FeatureT2XtPk, FeatureFP16,
+ FeatureAvoidPartialCPSR]>;
class ProcNoItin<string Name, list<SubtargetFeature> Features>
: Processor<Name, GenericItineraries, Features>;