[PATCHv2] Add a couple of A?CST1:CST2 match and simplify optimizations
apinski@marvell.com
apinski@marvell.com
Sun May 23 09:41:03 GMT 2021
From: Andrew Pinski <apinski@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.
Differences from V1:
* Use bit_xor 1 instead of bit_not to fix the problem with boolean types
which are not 1 bit precision.
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 | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/gcc/match.pd b/gcc/match.pd
index 1fc6b7b1557..ad6b057c56d 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3711,6 +3711,47 @@ 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, tree_log2 (@1));
+ }
+ (lshift (convert (convert:boolean_type_node @0)) { shift; })))))
+ (if (integer_zerop (@1))
+ (with {
+ tree booltrue = constant_boolean_node (true, boolean_type_node);
+ }
+ (switch
+ /* a ? 0 : 1 -> !a. */
+ (if (integer_onep (@2))
+ (convert (bit_xor (convert:boolean_type_node @0) { booltrue; } )))
+ /* a ? -1 : 0 -> -(!a). */
+ (if (integer_all_onesp (@2))
+ (negate (convert (bit_xor (convert:boolean_type_node @0) { booltrue; } ))))
+ /* a ? powerof2cst : 0 -> (!a) << (log2(powerof2cst)) */
+ (if (!POINTER_TYPE_P (type) && integer_pow2p (@2))
+ (with {
+ tree shift = build_int_cst (integer_type_node, tree_log2 (@2));
+ }
+ (lshift (convert (bit_xor (convert:boolean_type_node @0) { booltrue; } ))
+ { shift; }))))))))
+#endif
+
/* Simplification moved from fold_cond_expr_with_comparison. It may also
be extended. */
/* This pattern implements two kinds simplification:
--
2.17.1
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