On Thu, May 16, 2013 at 07:59:00PM +0200, Mikael Pettersson wrote: > Jakub Jelinek writes: > > On Thu, Apr 25, 2013 at 11:47:02PM +0200, Jakub Jelinek wrote: > > > This patch adds folding of constant arguments v>> and v<<, which helps to > > > optimize the testcase from the PR back into constant store after > vectorized > > > loop is unrolled. > > > > As this fixes a regression on the 4.8 branch, I've backported it (and > > minimal prerequisite for that) to 4.8 branch too. > > Unfortunately this patch makes gcc.dg/vect/no-scevccp-outer-{7,13}.c fail > on powerpc64-linux: > > +FAIL: gcc.dg/vect/no-scevccp-outer-13.c execution test > +FAIL: gcc.dg/vect/no-scevccp-outer-7.c execution test > > which is a regression from 4.8-20130502. Reverting r198580 fixes it. > > The same FAILs also occur on trunk.
Ah right, I was confused by the fact that VEC_RSHIFT_EXPR is used not just on little endian targets, but on big endian as well (VEC_LSHIFT_EXPR is never emitted), but the important spot is when extracting the scalar result from the vector: if (BYTES_BIG_ENDIAN) bitpos = size_binop (MULT_EXPR, bitsize_int (TYPE_VECTOR_SUBPARTS (vectype) - 1), TYPE_SIZE (scalar_type)); else bitpos = bitsize_zero_node; Fixed thusly, ok for trunk/4.8? 2013-05-17 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/57051 * fold-const.c (const_binop) <case VEC_LSHIFT_EXPR, case VEC_RSHIFT_EXPR>: Fix BYTES_BIG_ENDIAN handling. --- gcc/fold-const.c.jj 2013-05-16 12:36:28.000000000 +0200 +++ gcc/fold-const.c 2013-05-17 08:38:12.575117676 +0200 @@ -1393,7 +1393,7 @@ const_binop (enum tree_code code, tree a if (shiftc >= outerc || (shiftc % innerc) != 0) return NULL_TREE; int offset = shiftc / innerc; - if (code == VEC_LSHIFT_EXPR) + if ((code == VEC_RSHIFT_EXPR) ^ (!BYTES_BIG_ENDIAN)) offset = -offset; tree zero = build_zero_cst (TREE_TYPE (type)); for (i = 0; i < count; i++) Jakub