[PATCH v2 2/2] testsuite: derive the sign shift from sizeof in minmax-swar-1 and -2

[Dominic P]

The shift count was 31 under an int32 requirement, which left the rule
untested on every other int width.

Tested on x86_64-pc-linux-gnu, aarch64-linux-gnu and arm-none-eabi
(cortex-m0 soft).

Assisted-by: Claude Opus 5 (Anthropic)

gcc/testsuite/ChangeLog:

        * gcc.dg/tree-ssa/minmax-swar-1.c: Derive the shift count from
        sizeof (int); drop the int32 requirement.
        * gcc.dg/tree-ssa/minmax-swar-2.c: Likewise.

Signed-off-by: Dominic P <g...@gcc.dp11.uk>
---
 gcc/testsuite/gcc.dg/tree-ssa/minmax-swar-1.c | 20 ++++++++++---------
 gcc/testsuite/gcc.dg/tree-ssa/minmax-swar-2.c |  7 ++++---
 2 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/minmax-swar-1.c 
b/gcc/testsuite/gcc.dg/tree-ssa/minmax-swar-1.c
index 53bf1242cb8..1c7395af1d4 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/minmax-swar-1.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/minmax-swar-1.c
@@ -1,47 +1,49 @@
 /* { dg-do compile } */
 /* { dg-options "-O2 -fdump-tree-forwprop1 -fdump-tree-optimized" } */
-/* { dg-require-effective-target int32 } */
+
+#define SHIFT (sizeof (int) * __CHAR_BIT__ - 1)
 
 /* The branchless min and max that x264's x264_median writes.  The existing
-   rule turns x & (x >> 31) into MIN <x, 0>; these have to finish the job.  */
+   rule turns x & (x >> (precision - 1)) into MIN <x, 0>; these have to finish
+   the job.  */
 
 int
 swar_min (int a, int b)
 {
   int t = a - b;
-  return b + (t & (t >> 31));
+  return b + (t & (t >> SHIFT));
 }
 
 int
 swar_max (int a, int b)
 {
   int t = a - b;
-  return a - (t & (t >> 31));
+  return a - (t & (t >> SHIFT));
 }
 
 int
 swar_min_not (int a, int b)
 {
   int t = a - b;
-  return a - (t & ~(t >> 31));
+  return a - (t & ~(t >> SHIFT));
 }
 
 int
 swar_max_not (int a, int b)
 {
   int t = a - b;
-  return b + (t & ~(t >> 31));
+  return b + (t & ~(t >> SHIFT));
 }
 
 /* Both uses of the one difference have to fold.  */
 int
 swar_median (int a, int b, int c)
 {
-  int t = (a - b) & ((a - b) >> 31);
+  int t = (a - b) & ((a - b) >> SHIFT);
   a -= t;
   b += t;
-  b -= (b - c) & ((b - c) >> 31);
-  b += (a - b) & ((a - b) >> 31);
+  b -= (b - c) & ((b - c) >> SHIFT);
+  b += (a - b) & ((a - b) >> SHIFT);
   return b;
 }
 
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/minmax-swar-2.c 
b/gcc/testsuite/gcc.dg/tree-ssa/minmax-swar-2.c
index b600d69207e..0066b185abf 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/minmax-swar-2.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/minmax-swar-2.c
@@ -1,6 +1,7 @@
 /* { dg-do compile } */
 /* { dg-options "-O2 -fwrapv -fdump-tree-optimized" } */
-/* { dg-require-effective-target int32 } */
+
+#define SHIFT (sizeof (int) * __CHAR_BIT__ - 1)
 
 /* With a wrapping difference the identity fails: for a = INT_MIN, b = 1 the
    difference wraps positive and the branchless form returns b.  The inner
@@ -11,14 +12,14 @@ int
 swar_min (int a, int b)
 {
   int t = a - b;
-  return b + (t & (t >> 31));
+  return b + (t & (t >> SHIFT));
 }
 
 int
 swar_max (int a, int b)
 {
   int t = a - b;
-  return a - (t & (t >> 31));
+  return a - (t & (t >> SHIFT));
 }
 
 /* { dg-final { scan-tree-dump-times "MIN_EXPR <\[^,\]*, 0>" 2 "optimized" } } 
*/
-- 
2.55.0