* config/rs6000/rs6000.md (*lt0_disi): New.

From-SVN: r226006

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6a4b22bf6f3d0c6764bd5345126f4449c6e43373..953e6b999fbcf6735ff1eca431c3918ce1dc5d2b 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2015-07-20  Segher Boessenkool  <segher@kernel.crashing.org>
+
+       * config/rs6000/rs6000.md (*lt0_disi): New.
+
 2015-07-20  Segher Boessenkool  <segher@kernel.crashing.org>
 
        PR target/66217

diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index 5727068060c4d3f0476db58d60269865e5c1d9b0..4e64a365131d530afeb07a607b38d09e1684e703 100644 (file)
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -3475,6 +3475,17 @@
    (set_attr "dot" "yes")
    (set_attr "length" "4,8")])
 
+; Special case for less-than-0.  We can do it with just one machine
+; instruction, but the generic optimizers do not realise it is cheap.
+(define_insn "*lt0_disi"
+  [(set (match_operand:DI 0 "gpc_reg_operand" "=r")
+       (lt:DI (match_operand:SI 1 "gpc_reg_operand" "r")
+              (const_int 0)))]
+  "TARGET_POWERPC64"
+  "rlwinm %0,%1,1,31,31"
+  [(set_attr "type" "shift")])
+
+
 
 ; Two forms for insert (the two arms of the IOR are not canonicalized,
 ; both are an AND so are the same precedence).