procyberian/gcc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

tree-ssa-math-opts.c (convert_mult_to_fma): Do not verify that the target has the exact fma operation that we matched.

Browse source 
* tree-ssa-math-opts.c (convert_mult_to_fma): Do not verify
	that the target has the exact fma operation that we matched.

From-SVN: r166611
This commit is contained in:
Richard Henderson 2010-11-11 10:42:35 -08:00 • committed by Richard Henderson
parent 658bd5ca00
commit a1d8aa4b1f
2 changed files with 18 additions and 15 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
gcc/ChangeLog
View file

@ -1,3 +1,8 @@
2010-11-11 Richard Henderson <rth@redhat.com>
* tree-ssa-math-opts.c (convert_mult_to_fma): Do not verify
that the target has the exact fma operation that we matched.
2010-11-11 Joseph Myers <joseph@codesourcery.com>
* reginfo.c (fix_register): Avoid inserting English word in

28
gcc/tree-ssa-math-opts.c
View file

@ -1531,7 +1531,6 @@ convert_mult_to_fma (gimple mul_stmt)
enum tree_code use_code;
tree result = mul_result;
bool negate_p = false;
optab opt;
use_stmt = USE_STMT (use_p);
@ -1574,32 +1573,31 @@ convert_mult_to_fma (gimple mul_stmt)
negate_p = true;
}
/* Determine if the target supports the exact form we found. */
switch (use_code)
{
case MINUS_EXPR:
if (gimple_assign_rhs1 (use_stmt) == result)
{
opt = negate_p ? fnms_optab : fms_optab;
break;
}
negate_p = !negate_p;
/* FALLTHRU */
case PLUS_EXPR:
opt = negate_p ? fnma_optab : fma_optab;
if (gimple_assign_rhs2 (use_stmt) == result)
negate_p = !negate_p;
break;
case PLUS_EXPR:
break;
default:
/* FMA can only be formed from PLUS and MINUS. */
return false;
}
if (optab_handler (opt, TYPE_MODE (type)) == CODE_FOR_nothing)
return false;
/* We can't handle a * b + a * b. */
if (gimple_assign_rhs1 (use_stmt) == gimple_assign_rhs2 (use_stmt))
return false;
/* While it is possible to validate whether or not the exact form
that we've recognized is available in the backend, the assumption
is that the transformation is never a loss. For instance, suppose
the target only has the plain FMA pattern available. Consider
a*b-c -> fma(a,b,-c): we've exchanged MUL+SUB for FMA+NEG, which
is still two operations. Consider -(a*b)-c -> fma(-a,b,-c): we
still have 3 operations, but in the FMA form the two NEGs are
independant and could be run in parallel. */
}
FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, mul_result)