ARM: Support SIMD reduction for 32-bit backend.

Support SIMD reduction (add, min, max) and SAD (for int->int only)
idioms for arm (32-bit) backend.

Test: test-art-target, test-art-host
Test: 661-checker-simd-reduc, 660-checker-simd-sad-int

Change-Id: Ic6121f5d781a9bcedc33041b6c4ecafad9b0420a
diff --git a/compiler/optimizing/loop_optimization.h b/compiler/optimizing/loop_optimization.h
index b1b3d11..768fe55 100644
--- a/compiler/optimizing/loop_optimization.h
+++ b/compiler/optimizing/loop_optimization.h
@@ -78,6 +78,7 @@
     kNoStringCharAt  = 1 << 9,   // no StringCharAt
     kNoReduction     = 1 << 10,  // no reduction
     kNoSAD           = 1 << 11,  // no sum of absolute differences (SAD)
+    kNoWideSAD       = 1 << 12,  // no sum of absolute differences (SAD) with operand widening
   };
 
   /*