On Mon, 24 Apr 2017, Richard Biener wrote:
>
> One issue in PR79201 is that we don't sink pure/const calls which is
> what the following simple patch fixes.
>
> Bootstrap and regtest running on x86_64-unknown-linux-gnu.
Needed some gimple_assign_lhs -> gimple_get_lhs adjustments and
adjustment of gcc.target/i386/pr22152.c where we now sink the
assignment out of the pointless loop. Not sure what the original
bug was about (well, reg allocation) so I simply disabled sinking
for it.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2017-04-25 Richard Biener <rguent...@suse.de>
PR tree-optimization/79201
* tree-ssa-sink.c (statement_sink_location): Handle calls.
* gcc.dg/tree-ssa/ssa-sink-16.c: New testcase.
* gcc.target/i386/pr22152.c: Disable sinking.
Index: gcc/tree-ssa-sink.c
===================================================================
*** gcc/tree-ssa-sink.c (revision 247092)
--- gcc/tree-ssa-sink.c (working copy)
*************** statement_sink_location (gimple *stmt, b
*** 256,263 ****
*zero_uses_p = false;
! /* We only can sink assignments. */
! if (!is_gimple_assign (stmt))
return false;
/* We only can sink stmts with a single definition. */
--- 257,268 ----
*zero_uses_p = false;
! /* We only can sink assignments and non-looping const/pure calls. */
! int cf;
! if (!is_gimple_assign (stmt)
! && (!is_gimple_call (stmt)
! || !((cf = gimple_call_flags (stmt)) & (ECF_CONST|ECF_PURE))
! || (cf & ECF_LOOPING_CONST_OR_PURE)))
return false;
/* We only can sink stmts with a single definition. */
*************** statement_sink_location (gimple *stmt, b
*** 291,297 ****
if (stmt_ends_bb_p (stmt)
|| gimple_has_side_effects (stmt)
|| (cfun->has_local_explicit_reg_vars
! && TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt))) == BLKmode))
return false;
/* Return if there are no immediate uses of this stmt. */
--- 296,302 ----
if (stmt_ends_bb_p (stmt)
|| gimple_has_side_effects (stmt)
|| (cfun->has_local_explicit_reg_vars
! && TYPE_MODE (TREE_TYPE (gimple_get_lhs (stmt))) == BLKmode))
return false;
/* Return if there are no immediate uses of this stmt. */
*************** statement_sink_location (gimple *stmt, b
*** 323,337 ****
/* A killing definition is not a use. */
if ((gimple_has_lhs (use_stmt)
! && operand_equal_p (gimple_assign_lhs (stmt),
gimple_get_lhs (use_stmt), 0))
! || stmt_kills_ref_p (use_stmt, gimple_assign_lhs (stmt)))
{
/* If use_stmt is or might be a nop assignment then USE_STMT
acts as a use as well as definition. */
if (stmt != use_stmt
&& ref_maybe_used_by_stmt_p (use_stmt,
! gimple_assign_lhs (stmt)))
return false;
continue;
}
--- 328,342 ----
/* A killing definition is not a use. */
if ((gimple_has_lhs (use_stmt)
! && operand_equal_p (gimple_get_lhs (stmt),
gimple_get_lhs (use_stmt), 0))
! || stmt_kills_ref_p (use_stmt, gimple_get_lhs (stmt)))
{
/* If use_stmt is or might be a nop assignment then USE_STMT
acts as a use as well as definition. */
if (stmt != use_stmt
&& ref_maybe_used_by_stmt_p (use_stmt,
! gimple_get_lhs (stmt)))
return false;
continue;
}
Index: gcc/testsuite/gcc.dg/tree-ssa/ssa-sink-16.c
===================================================================
*** gcc/testsuite/gcc.dg/tree-ssa/ssa-sink-16.c (nonexistent)
--- gcc/testsuite/gcc.dg/tree-ssa/ssa-sink-16.c (working copy)
***************
*** 0 ****
--- 1,14 ----
+ /* { dg-do compile } */
+ /* Note PRE rotates the loop and blocks the sinking opportunity. */
+ /* { dg-options "-O2 -fno-tree-pre -fdump-tree-sink -fdump-tree-optimized" }
*/
+
+ int f(int n)
+ {
+ int i,j=0;
+ for (i = 0; i < 31; i++)
+ j = __builtin_ffs(i);
+ return j;
+ }
+
+ /* { dg-final { scan-tree-dump "Sinking j_. = __builtin_ffs" "sink" } } */
+ /* { dg-final { scan-tree-dump "return 2;" "optimized" } } */
Index: gcc/testsuite/gcc.target/i386/pr22152.c
===================================================================
*** gcc/testsuite/gcc.target/i386/pr22152.c (revision 247092)
--- gcc/testsuite/gcc.target/i386/pr22152.c (working copy)
***************
*** 1,5 ****
/* { dg-do compile } */
! /* { dg-options "-O2 -msse2 -mtune=core2" } */
/* { dg-additional-options "-mno-vect8-ret-in-mem" { target *-*-vxworks* } }
*/
/* { dg-additional-options "-mabi=sysv" { target x86_64-*-mingw* } } */
--- 1,5 ----
/* { dg-do compile } */
! /* { dg-options "-O2 -fno-tree-sink -msse2 -mtune=core2" } */
/* { dg-additional-options "-mno-vect8-ret-in-mem" { target *-*-vxworks* } }
*/
/* { dg-additional-options "-mabi=sysv" { target x86_64-*-mingw* } } */
