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File _service:tar_scm:0059-Backport-Add-a-couple-of-A-CST1-CST2-match-and-simpl.patch of Package gcc (Revision f9d0714ae2109e7cb01b9cd1a741e37e)

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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