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[1/3] MATCH: Allow unsigned types for `X & -Y -> X * Y` pattern

Message ID 20230607213217.3052696-1-apinski@marvell.com
State Accepted
Headers
Series [1/3] MATCH: Allow unsigned types for `X & -Y -> X * Y` pattern |

Checks

Context Check Description
snail/gcc-patch-check success Github commit url

Commit Message

Andrew Pinski June 7, 2023, 9:32 p.m. UTC 
  This allows unsigned types if the inner type where the negation is
located has greater than or equal to precision than the outer type.

branchless-cond.c needs to be updated since now we change it to
use a multiply rather than still having (-a)&c in there.

OK? Bootstrapped and tested on x86_64-linux-gnu.

gcc/ChangeLog:

	* match.pd (`X & -Y -> X * Y`): Allow for truncation
	and the same type for unsigned types.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/branchless-cond.c: Update testcase.
---
 gcc/match.pd                                    | 5 ++++-
 gcc/testsuite/gcc.dg/tree-ssa/branchless-cond.c | 6 +++---
 2 files changed, 7 insertions(+), 4 deletions(-)

Comments

Jeff Law June 7, 2023, 10:45 p.m. UTC | #1 
On 6/7/23 15:32, Andrew Pinski via Gcc-patches wrote:
> This allows unsigned types if the inner type where the negation is
> located has greater than or equal to precision than the outer type.
> 
> branchless-cond.c needs to be updated since now we change it to
> use a multiply rather than still having (-a)&c in there.
> 
> OK? Bootstrapped and tested on x86_64-linux-gnu.
> 
> gcc/ChangeLog:
> 
> 	* match.pd (`X & -Y -> X * Y`): Allow for truncation
> 	and the same type for unsigned types.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* gcc.dg/tree-ssa/branchless-cond.c: Update testcase.
OK.
jeff
diff mbox series

Patch

diff --git a/gcc/match.pd b/gcc/match.pd
index 4ad037d641a..7b95b63cee4 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2058,7 +2058,10 @@  DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
  (if (INTEGRAL_TYPE_P (type)
       && INTEGRAL_TYPE_P (TREE_TYPE (@0))
       && TREE_CODE (TREE_TYPE (@0)) != BOOLEAN_TYPE
-      && !TYPE_UNSIGNED (TREE_TYPE (@0)))
+      /* Sign extending of the neg or a truncation of the neg
+         is needed. */
+      && (!TYPE_UNSIGNED (TREE_TYPE (@0))
+	  || TYPE_PRECISION (type) <= TYPE_PRECISION (TREE_TYPE (@0))))
   (mult (convert @0) @1)))
 
 /* Narrow integer multiplication by a zero_one_valued_p operand.
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/branchless-cond.c b/gcc/testsuite/gcc.dg/tree-ssa/branchless-cond.c
index 68087ae6568..e063dc4bb5f 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/branchless-cond.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/branchless-cond.c
@@ -21,6 +21,6 @@  int f4(unsigned int x, unsigned int y, unsigned int z)
   return ((x & 1) != 0) ? z | y : y;
 }
 
-/* { dg-final { scan-tree-dump-times " -" 4 "optimized" } } */
-/* { dg-final { scan-tree-dump-times " & " 8 "optimized" } } */
-/* { dg-final { scan-tree-dump-not "if" "optimized" } } */
+/* { dg-final { scan-tree-dump-times " \\\*" 4 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " & " 4 "optimized" } } */
+/* { dg-final { scan-tree-dump-not "if " "optimized" } } */