tree-optimization/105629 - spaceship recognition regression

With the extra GENERIC folding we now do to
(unsigned int) __v._M_value & 1 != (unsigned int) __v._M_value
we end up with a sign-extending conversion to unsigned int
rather than the sign-conversion to unsigned char we expect.
Relaxing that fixes the regression.

2022-05-23  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/105629
	* tree-ssa-phiopt.cc (spaceship_replacement): Allow
	a sign-extending conversion.

diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
index 8c9c46d..e61d973 100644 (file)
--- a/gcc/tree-ssa-phiopt.cc
+++ b/gcc/tree-ssa-phiopt.cc
@@ -2217,7 +2217,7 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
 
       if (!TYPE_UNSIGNED (ty2) || !INTEGRAL_TYPE_P (ty2))
        return false;
-      if (TYPE_PRECISION (ty1) != TYPE_PRECISION (ty2))
+      if (TYPE_PRECISION (ty1) > TYPE_PRECISION (ty2))
        return false;
       if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig_use_lhs))
        return false;