Here it is, the patch that enables auto-vectorization for 32bit modes.

Sent as RFC, because the patch fails some vectorizer scans, as it
obviously enables more vectorization to happen:

Running target unix
FAIL: gcc.dg/vect/pr71264.c -flto -ffat-lto-objects  scan-tree-dump
vect "vectorized 1 loops in function"
FAIL: gcc.dg/vect/pr71264.c scan-tree-dump vect "vectorized 1 loops in function"
FAIL: gcc.dg/vect/slp-28.c -flto -ffat-lto-objects
scan-tree-dump-times vect "vectorized 1 loops" 1
FAIL: gcc.dg/vect/slp-28.c -flto -ffat-lto-objects
scan-tree-dump-times vect "vectorizing stmts using SLP" 1
FAIL: gcc.dg/vect/slp-28.c scan-tree-dump-times vect "vectorized 1 loops" 1
FAIL: gcc.dg/vect/slp-28.c scan-tree-dump-times vect "vectorizing
stmts using SLP" 1
FAIL: gcc.dg/vect/slp-3.c -flto -ffat-lto-objects
scan-tree-dump-times vect "vectorized 3 loops" 1
FAIL: gcc.dg/vect/slp-3.c -flto -ffat-lto-objects
scan-tree-dump-times vect "vectorizing stmts using SLP" 3
FAIL: gcc.dg/vect/slp-3.c scan-tree-dump-times vect "vectorized 3 loops" 1
FAIL: gcc.dg/vect/slp-3.c scan-tree-dump-times vect "vectorizing stmts
using SLP" 3


Running target unix/-m32
FAIL: gcc.dg/vect/no-vfa-vect-101.c scan-tree-dump-times vect "can't
determine dependence" 1
FAIL: gcc.dg/vect/no-vfa-vect-102.c scan-tree-dump-times vect
"possible dependence between data-refs" 1
FAIL: gcc.dg/vect/no-vfa-vect-102a.c scan-tree-dump-times vect
"possible dependence between data-refs" 1
FAIL: gcc.dg/vect/no-vfa-vect-37.c scan-tree-dump-times vect "can't
determine dependence" 2
FAIL: gcc.dg/vect/pr71264.c -flto -ffat-lto-objects  scan-tree-dump
vect "vectorized 1 loops in function"
FAIL: gcc.dg/vect/pr71264.c scan-tree-dump vect "vectorized 1 loops in function"
FAIL: gcc.dg/vect/slp-28.c -flto -ffat-lto-objects
scan-tree-dump-times vect "vectorized 1 loops" 1
FAIL: gcc.dg/vect/slp-28.c -flto -ffat-lto-objects
scan-tree-dump-times vect "vectorizing stmts using SLP" 1
FAIL: gcc.dg/vect/slp-28.c scan-tree-dump-times vect "vectorized 1 loops" 1
FAIL: gcc.dg/vect/slp-28.c scan-tree-dump-times vect "vectorizing
stmts using SLP" 1
FAIL: gcc.dg/vect/slp-3.c -flto -ffat-lto-objects
scan-tree-dump-times vect "vectorized 3 loops" 1
FAIL: gcc.dg/vect/slp-3.c -flto -ffat-lto-objects
scan-tree-dump-times vect "vectorizing stmts using SLP" 3
FAIL: gcc.dg/vect/slp-3.c scan-tree-dump-times vect "vectorized 3 loops" 1
FAIL: gcc.dg/vect/slp-3.c scan-tree-dump-times vect "vectorizing stmts
using SLP" 3
FAIL: gcc.dg/vect/vect-104.c -flto -ffat-lto-objects
scan-tree-dump-times vect "possible dependence between data-refs" 1
FAIL: gcc.dg/vect/vect-104.c scan-tree-dump-times vect "possible
dependence between data-refs" 1

Please also note that V4QI and V2HI modes do not use MMX registers, so
auto-vectorization can also be enabled on 32bit x86 targets.

Uros.