When the optab causes the actual mode to be wider we have to re-check
whether we still fulfill the gimple constraints we verify.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2012-03-07 Richard Guenther <rguent...@suse.de>
* tree-ssa-math-opts.c (convert_mult_to_widen): Check actual
precision against gimple constraints.
Index: gcc/tree-ssa-math-opts.c
===================================================================
*** gcc/tree-ssa-math-opts.c (revision 185025)
--- gcc/tree-ssa-math-opts.c (working copy)
*************** convert_mult_to_widen (gimple stmt, gimp
*** 2158,2163 ****
--- 2158,2165 ----
/* Ensure that the inputs to the handler are in the correct precison
for the opcode. This will be the full mode size. */
actual_precision = GET_MODE_PRECISION (actual_mode);
+ if (2 * actual_precision > TYPE_PRECISION (type))
+ return false;
if (actual_precision != TYPE_PRECISION (type1)
|| from_unsigned1 != TYPE_UNSIGNED (type1))
{
