[PATCH] Add a couple of A?CST1:CST2 match and simplify optimizations

[apinski--- via Gcc-patches]

From: Andrew Pinski <apin...@marvell.com>

Instead of some of the more manual optimizations inside phi-opt,
it would be good idea to do a lot of the heavy lifting inside match
and simplify instead. In the process, this moves the three simple
A?CST1:CST2 (where CST1 or CST2 is zero) simplifications.

OK? Boostrapped and tested on x86_64-linux-gnu with no regressions.

Thanks,
Andrew Pinski

gcc:
* match.pd (A?CST1:CST2): Add simplifcations for A?0:+-1, A?+-1:0,
A?POW2:0 and A?0:POW2.
---
 gcc/match.pd | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/gcc/match.pd b/gcc/match.pd
index 10503b97ab5..844f7dd5f87 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3711,6 +3711,43 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
    (if (integer_all_onesp (@1) && integer_zerop (@2))
     @0))))
 
+/* A few simplifications of "a ? CST1 : CST2". */
+/* NOTE: Only do this on gimple as the if-chain-to-switch
+   optimization depends on the gimple to have if statements in it. */
+#if GIMPLE
+(simplify
+ (cond @0 INTEGER_CST@1 INTEGER_CST@2)
+ (switch
+  (if (integer_zerop (@2))
+   (switch
+    /* a ? 1 : 0 -> a if 0 and 1 are integral types. */
+    (if (integer_onep (@1))
+     (convert (convert:boolean_type_node @0)))
+    /* a ? -1 : 0 -> -a. */
+    (if (integer_all_onesp (@1))
+     (negate (convert (convert:boolean_type_node @0))))
+    /* a ? powerof2cst : 0 -> a << (log2(powerof2cst)) */
+    (if (!POINTER_TYPE_P (type) && integer_pow2p (@1))
+     (with {
+       tree shift = build_int_cst (integer_type_node, wi::exact_log2 
(wi::to_wide (@1)));
+      }
+      (lshift (convert (convert:boolean_type_node @0)) { shift; })))))
+  (if (integer_zerop (@1))
+   (switch
+    /* a ? 0 : 1 -> !a. */
+    (if (integer_onep (@2))
+     (convert (bit_not:boolean_type_node (convert:boolean_type_node @0))))
+    /* a ? -1 : 0 -> -(!a). */
+    (if (integer_all_onesp (@2))
+     (negate (convert (bit_not:boolean_type_node (convert:boolean_type_node 
@0)))))
+    /* a ? powerof2cst : 0 -> (!a) << (log2(powerof2cst)) */
+    (if (!POINTER_TYPE_P (type) && integer_pow2p (@2))
+     (with {
+       tree shift = build_int_cst (integer_type_node, wi::exact_log2 
(wi::to_wide (@2)));
+      }
+      (lshift (convert (bit_not:boolean_type_node (convert:boolean_type_node 
@0))) { shift; })))))))
+#endif
+
 /* Simplification moved from fold_cond_expr_with_comparison.  It may also
    be extended.  */
 /* This pattern implements two kinds simplification:
-- 
2.27.0