On 26 January 2018 at 11:25, Richard Biener <rguent...@suse.de> wrote: > On Thu, 25 Jan 2018, Richard Biener wrote: > >> On Thu, 25 Jan 2018, Marc Glisse wrote: >> >> > On Thu, 25 Jan 2018, Richard Biener wrote: >> > >> > > --- gcc/match.pd (revision 257047) >> > > +++ gcc/match.pd (working copy) >> > > @@ -1939,6 +1939,37 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) >> > > (minus (convert (view_convert:stype @1)) >> > > (convert (view_convert:stype @2))))))) >> > > >> > > +/* (A * C) +- (B * C) -> (A+-B) * C and (A * C) +- A -> A * (C+-1). >> > > + Modeled after fold_plusminus_mult_expr. */ >> > > +(if (!TYPE_SATURATING (type) >> > > + && (!FLOAT_TYPE_P (type) || flag_associative_math)) >> > > + (for plusminus (plus minus) >> > > + (simplify >> > > + (plusminus (mult:s @0 @1) (mult:cs @0 @2)) >> > >> > No :c on the first mult, so we don't actually handle A*C+B*C? >> >> Hmm, I somehow convinced myself that it's only necessary on one >> of the mults... but you are of course right. Will re-test with >> that fixed. > > This is what I have applied. Note I had to XFAIL a minor part of > gcc.dg/tree-ssa/loop-15.c, namely simplifying the final value > replacement down to n * n. While the patch should enable this > the place where the transform could trigger with enough information > about n is VRP but that doesn't end up folding all stmts - and > that's something I'm not willing to change right now. > > Bootstrapped and tested on x86_64-unknown-linux-gnu, applied on trunk. >
Hi, I think this patch caused regressions on aarch64: FAIL: gcc.dg/wmul-1.c scan-tree-dump-not widening_mul "WIDEN_MULT_PLUS_EXPR" Thanks, Christophe > Richard. > > 2018-01-26 Richard Biener <rguent...@suse.de> > > PR tree-optimization/81082 > * fold-const.c (fold_plusminus_mult_expr): Do not perform the > association if it requires casting to unsigned. > * match.pd ((A * C) +- (B * C) -> (A+-B)): New patterns derived > from fold_plusminus_mult_expr to catch important cases late when > range info is available. > > * gcc.dg/vect/pr81082.c: New testcase. > * gcc.dg/tree-ssa/loop-15.c: XFAIL the (int)((unsigned)n + -1U) * n + > n > simplification to n * n. > > Index: gcc/fold-const.c > =================================================================== > --- gcc/fold-const.c (revision 257047) > +++ gcc/fold-const.c (working copy) > @@ -7097,7 +7097,7 @@ fold_plusminus_mult_expr (location_t loc > > /* Same may be zero and thus the operation 'code' may overflow. Likewise > same may be minus one and thus the multiplication may overflow. Perform > - the operations in an unsigned type. */ > + the sum operation in an unsigned type. */ > tree utype = unsigned_type_for (type); > tree tem = fold_build2_loc (loc, code, utype, > fold_convert_loc (loc, utype, alt0), > @@ -7110,9 +7110,9 @@ fold_plusminus_mult_expr (location_t loc > return fold_build2_loc (loc, MULT_EXPR, type, > fold_convert (type, tem), same); > > - return fold_convert_loc (loc, type, > - fold_build2_loc (loc, MULT_EXPR, utype, tem, > - fold_convert_loc (loc, utype, > same))); > + /* Do not resort to unsigned multiplication because > + we lose the no-overflow property of the expression. */ > + return NULL_TREE; > } > > /* Subroutine of native_encode_expr. Encode the INTEGER_CST > Index: gcc/match.pd > =================================================================== > --- gcc/match.pd (revision 257047) > +++ gcc/match.pd (working copy) > @@ -1939,6 +1939,37 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) > (minus (convert (view_convert:stype @1)) > (convert (view_convert:stype @2))))))) > > +/* (A * C) +- (B * C) -> (A+-B) * C and (A * C) +- A -> A * (C+-1). > + Modeled after fold_plusminus_mult_expr. */ > +(if (!TYPE_SATURATING (type) > + && (!FLOAT_TYPE_P (type) || flag_associative_math)) > + (for plusminus (plus minus) > + (simplify > + (plusminus (mult:cs @0 @1) (mult:cs @0 @2)) > + (if (!ANY_INTEGRAL_TYPE_P (type) > + || TYPE_OVERFLOW_WRAPS (type) > + || (INTEGRAL_TYPE_P (type) > + && tree_expr_nonzero_p (@0) > + && expr_not_equal_to (@0, wi::minus_one (TYPE_PRECISION (type))))) > + (mult (plusminus @1 @2) @0))) > + /* We cannot generate constant 1 for fract. */ > + (if (!ALL_FRACT_MODE_P (TYPE_MODE (type))) > + (simplify > + (plusminus @0 (mult:cs @0 @2)) > + (if (!ANY_INTEGRAL_TYPE_P (type) > + || TYPE_OVERFLOW_WRAPS (type) > + || (INTEGRAL_TYPE_P (type) > + && tree_expr_nonzero_p (@0) > + && expr_not_equal_to (@0, wi::minus_one (TYPE_PRECISION > (type))))) > + (mult (plusminus { build_one_cst (type); } @2) @0))) > + (simplify > + (plusminus (mult:cs @0 @2) @0) > + (if (!ANY_INTEGRAL_TYPE_P (type) > + || TYPE_OVERFLOW_WRAPS (type) > + || (INTEGRAL_TYPE_P (type) > + && tree_expr_nonzero_p (@0) > + && expr_not_equal_to (@0, wi::minus_one (TYPE_PRECISION > (type))))) > + (mult (plusminus @2 { build_one_cst (type); }) @0)))))) > > /* Simplifications of MIN_EXPR, MAX_EXPR, fmin() and fmax(). */ > > Index: gcc/testsuite/gcc.dg/vect/pr81082.c > =================================================================== > --- gcc/testsuite/gcc.dg/vect/pr81082.c (revision 0) > +++ gcc/testsuite/gcc.dg/vect/pr81082.c (working copy) > @@ -0,0 +1,15 @@ > +/* { dg-do compile } */ > +/* { dg-require-effective-target vect_int } */ > + > +int > +f (int *x, int b1, int b2, int b3) > +{ > + int foo = 0; > + for (int i1 = 0; i1 < b1; ++i1) > + for (int i2 = 0; i2 < b2; ++i2) > + for (int i3 = 0; i3 < b3; ++i3) > + foo += x[i1 * b2 * b3 + i2 * b3 + (i3 - 1)]; > + return foo; > +} > + > +/* { dg-final { scan-tree-dump "vectorized 1 loops in function" "vect" } } */ > Index: gcc/testsuite/gcc.dg/tree-ssa/loop-15.c > =================================================================== > --- gcc/testsuite/gcc.dg/tree-ssa/loop-15.c (revision 257048) > +++ gcc/testsuite/gcc.dg/tree-ssa/loop-15.c (working copy) > @@ -19,7 +19,7 @@ int bla(void) > } > > /* Since the loop is removed, there should be no addition. */ > -/* { dg-final { scan-tree-dump-times " \\+ " 0 "optimized" } } */ > +/* { dg-final { scan-tree-dump-times " \\+ " 0 "optimized" { xfail *-*-* } } > } */ > /* { dg-final { scan-tree-dump-times " \\* " 1 "optimized" } } */ > > /* The if from the loop header copying remains in the code. */