Add an ARM "feature". Cortex-a8 fp comparison is very slow (> 20 cycles).

llvm-svn: 108256
diff --git a/llvm/lib/Target/ARM/ARM.td b/llvm/lib/Target/ARM/ARM.td
index f1e6a9f..fa64d6c 100644
--- a/llvm/lib/Target/ARM/ARM.td
+++ b/llvm/lib/Target/ARM/ARM.td
@@ -48,6 +48,8 @@
                                      "Enable divide instructions">;
 def FeatureT2ExtractPack: SubtargetFeature<"t2xtpk", "HasT2ExtractPack", "true",
                                  "Enable Thumb2 extract and pack instructions">;
+def FeatureSlowFPBrcc : SubtargetFeature<"slow-fp-brcc", "SlowFPBrcc", "true",
+                                         "FP compare + branch is slow">;
 
 // Some processors have multiply-accumulate instructions that don't
 // play nicely with other VFP instructions, and it's generally better
@@ -129,7 +131,7 @@
 // V7 Processors.
 def : Processor<"cortex-a8",        CortexA8Itineraries,
                 [ArchV7A, FeatureThumb2, FeatureNEON, FeatureHasSlowVMLx,
-                 FeatureNEONForFP, FeatureT2ExtractPack]>;
+                 FeatureSlowFPBrcc, FeatureNEONForFP, FeatureT2ExtractPack]>;
 def : Processor<"cortex-a9",        CortexA9Itineraries,
                 [ArchV7A, FeatureThumb2, FeatureNEON, FeatureT2ExtractPack]>;
 def : ProcNoItin<"cortex-m3",       [ArchV7M, FeatureThumb2, FeatureHWDiv]>;