In the PR we perform expression replacement of an FP operation
across a builtin call that sets the FP control register. This
patch restricts replacement across calls further, from allowing
all builtins to only allowing those without side-effects.
Allowing replacement over calls at all was to not pessimize
FP code generation for example for sqrt which is most often
expanded to a single instruction.
Bootstrap and regtest running on x86_64-unknown-linux-gnu.
Comments?
Thanks,
Richard.
2012-12-20 Richard Biener <rguent...@suse.de>
PR middle-end/55752
* tree-ssa-ter.c (find_replaceable_in_bb): Only allow replacing
across calls with no side-effects.
Index: gcc/tree-ssa-ter.c
===================================================================
*** gcc/tree-ssa-ter.c (revision 194632)
--- gcc/tree-ssa-ter.c (working copy)
*************** find_replaceable_in_bb (temp_expr_table_
*** 681,692 ****
kill_expr (tab, partition);
}
! /* Increment counter if this is a non BUILT_IN call. We allow
! replacement over BUILT_IN calls since many will expand to inline
! insns instead of a true call. */
if (is_gimple_call (stmt)
! && !((fndecl = gimple_call_fndecl (stmt))
! && DECL_BUILT_IN (fndecl)))
cur_call_cnt++;
/* Now see if we are creating a new expression or not. */
--- 681,693 ----
kill_expr (tab, partition);
}
! /* Increment counter if this is not a BUILT_IN call without
! side-effects. We allow replacement over BUILT_IN calls
! since many will expand to inline insns instead of a true call. */
if (is_gimple_call (stmt)
! && (!((fndecl = gimple_call_fndecl (stmt))
! && DECL_BUILT_IN (fndecl))
! || gimple_has_side_effects (stmt)))
cur_call_cnt++;
/* Now see if we are creating a new expression or not. */
