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From 9f3a8c600abe16f172b36d8113862e8f7aea940c Mon Sep 17 00:00:00 2001
From: Andrew Pinski <apinski@marvell.com>
Date: Sun, 16 May 2021 13:07:06 -0700
Subject: [PATCH 11/35] [Backport] Add a couple of A?CST1:CST2 match and
simplify optimizations
Reference: https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=b6bdd7a4cb41ee057f2d064fffcb00f23ce6b497
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 | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)
diff --git a/gcc/match.pd b/gcc/match.pd
index 660d5c268..032830b0d 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3334,6 +3334,54 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(if (cst1 && cst2)
(vec_cond @0 { cst1; } { cst2; })))))
+/* 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 ? powerof2cst : 0 -> a << (log2(powerof2cst)) */
+ (if (INTEGRAL_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; })))
+ /* a ? -1 : 0 -> -a. No need to check the TYPE_PRECISION not being 1
+ here as the powerof2cst case above will handle that case correctly. */
+ (if (INTEGRAL_TYPE_P (type) && integer_all_onesp (@1))
+ (negate (convert (convert:boolean_type_node @0))))))
+ (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 ? powerof2cst : 0 -> (!a) << (log2(powerof2cst)) */
+ (if (INTEGRAL_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; })))
+ /* a ? -1 : 0 -> -(!a). No need to check the TYPE_PRECISION not being 1
+ here as the powerof2cst case above will handle that case correctly. */
+ (if (INTEGRAL_TYPE_P (type) && integer_all_onesp (@2))
+ (negate (convert (bit_xor (convert:boolean_type_node @0) { booltrue; } ))))
+ )
+ )
+ )
+ )
+)
+#endif
+
/* Simplification moved from fold_cond_expr_with_comparison. It may also
be extended. */
/* This pattern implements two kinds simplification:
--
2.27.0.windows.1
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