MATCH: Add some more value_replacement simplifications (a != 0 ? expr : 0) to match

This adds a few more of what is currently done in phiopt's value_replacement
to match. I noticed this when I was hooking up phiopt's value_replacement
code to use match and disabling the old code. But this can be done
independently from the hooking up phiopt's value_replacement as phiopt
is already hooked up for simplified versions already.

/* a != 0 ? a / b : 0  -> a / b iff b is nonzero. */
/* a != 0 ? a * b : 0 -> a * b */
/* a != 0 ? a & b : 0 -> a & b */

We prefer the `cond ? a : 0` forms to allow optimization of `a * cond` which
uses that form.

Bootstrapped and tested on x86_64-linux-gnu with no regressions.

	PR tree-optimization/114894

gcc/ChangeLog:

	* match.pd (`a != 0 ? a / b : 0`): New pattern.
	(`a != 0 ? a * b : 0`): New pattern.
	(`a != 0 ? a & b : 0`): New pattern.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/phi-opt-value-5.c: New test.

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/gcc/match.pd b/gcc/match.pd
index d401e75..03a03c3 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -4290,6 +4290,24 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   (cond (eq @0 integer_all_onesp) @1 (op:c@2 @1 @0))
    @2))
 
+/* a != 0 ? a / b : 0  -> a / b iff b is nonzero. */
+(for op (trunc_div ceil_div floor_div round_div exact_div)
+ (simplify
+  (cond (ne @0 integer_zerop) (op@2 @3 @1) integer_zerop )
+   (if (bitwise_equal_p (@0, @3)
+        && tree_expr_nonzero_p (@1))
+    @2)))
+
+/* Note we prefer the != case here
+   as (a != 0) * (a * b) will generate that version. */
+/* a != 0 ? a * b : 0 -> a * b */
+/* a != 0 ? a & b : 0 -> a & b */
+(for op (mult bit_and)
+ (simplify
+  (cond (ne @0 integer_zerop) (op:c@2 @1 @3) integer_zerop)
+  (if (bitwise_equal_p (@0, @3))
+   @2)))
+
 /* Simplifications of shift and rotates.  */
 
 (for rotate (lrotate rrotate)