> -----Original Message----- > From: Jakub Jelinek <ja...@redhat.com> > Sent: Thursday, November 4, 2021 4:11 PM > To: Tamar Christina <tamar.christ...@arm.com> > Cc: Jonathan Wakely <jwak...@redhat.com>; Richard Biener > <rguent...@suse.de>; gcc-patches@gcc.gnu.org; nd <n...@arm.com> > Subject: Re: [PATCH] middle-end: fix de-optimizations with bitclear patterns > on signed values > > On Thu, Nov 04, 2021 at 12:19:34PM +0000, Tamar Christina wrote: > > I'm not sure the precision matters since if the conversion resulted in > > not enough precision such that It influences the compare it would have > been optimized out. > > You can't really rely on other optimizations being performed. They will > usually happen, but might not because such code only materialized short > time ago without folding happening in between, or some debug counters or - > fno-* disabling some passes, ...
Fair point, I have separated out the logic as you requested and added the debug
fix.
Bootstrapped Regtested on aarch64-none-linux-gnu,
x86_64-pc-linux-gnu and no regressions.
Ok for master?
Thanks,
Tamar
gcc/ChangeLog:
* tree-ssa-phiopt.c (spaceship_replacement): Handle new canonical
codegen.
--- inline copy of patch ---
diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index
0e339c46afa29fa97f90d9bc4394370cd9b4b396..3ad5b23885a37eec0beff229e2a96e86658b2d1a
100644
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -2038,11 +2038,36 @@ spaceship_replacement (basic_block cond_bb, basic_block
middle_bb,
gimple *orig_use_stmt = use_stmt;
tree orig_use_lhs = NULL_TREE;
int prec = TYPE_PRECISION (TREE_TYPE (phires));
- if (is_gimple_assign (use_stmt)
- && gimple_assign_rhs_code (use_stmt) == BIT_AND_EXPR
- && TREE_CODE (gimple_assign_rhs2 (use_stmt)) == INTEGER_CST
- && (wi::to_wide (gimple_assign_rhs2 (use_stmt))
- == wi::shifted_mask (1, prec - 1, false, prec)))
+ bool is_cast = false;
+
+ /* Deal with the case when match.pd has rewritten the (res & ~1) == 0
+ into res <= 1 and has left a type-cast for signed types. */
+ if (gimple_assign_cast_p (use_stmt))
+ {
+ orig_use_lhs = gimple_assign_lhs (use_stmt);
+ /* match.pd would have only done this for a signed type,
+ so the conversion must be to an unsigned one. */
+ tree ty1 = TREE_TYPE (gimple_assign_rhs1 (use_stmt));
+ tree ty2 = TREE_TYPE (orig_use_lhs);
+
+ if (!TYPE_UNSIGNED (ty2) || !INTEGRAL_TYPE_P (ty2))
+ return false;
+ if (TYPE_PRECISION (ty1) != TYPE_PRECISION (ty2))
+ return false;
+ if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig_use_lhs))
+ return false;
+ if (EDGE_COUNT (phi_bb->preds) != 4)
+ return false;
+ if (!single_imm_use (orig_use_lhs, &use_p, &use_stmt))
+ return false;
+
+ is_cast = true;
+ }
+ else if (is_gimple_assign (use_stmt)
+ && gimple_assign_rhs_code (use_stmt) == BIT_AND_EXPR
+ && TREE_CODE (gimple_assign_rhs2 (use_stmt)) == INTEGER_CST
+ && (wi::to_wide (gimple_assign_rhs2 (use_stmt))
+ == wi::shifted_mask (1, prec - 1, false, prec)))
{
/* For partial_ordering result operator>= with unspec as second
argument is (res & 1) == res, folded by match.pd into
@@ -2099,7 +2124,7 @@ spaceship_replacement (basic_block cond_bb, basic_block
middle_bb,
|| !tree_fits_shwi_p (rhs)
|| !IN_RANGE (tree_to_shwi (rhs), -1, 1))
return false;
- if (orig_use_lhs)
+ if (orig_use_lhs && !is_cast)
{
if ((cmp != EQ_EXPR && cmp != NE_EXPR) || !integer_zerop (rhs))
return false;
@@ -2310,62 +2335,101 @@ spaceship_replacement (basic_block cond_bb,
basic_block middle_bb,
one_cmp = GT_EXPR;
enum tree_code res_cmp;
- switch (cmp)
+
+ if (is_cast)
{
- case EQ_EXPR:
- if (integer_zerop (rhs))
- res_cmp = EQ_EXPR;
- else if (integer_minus_onep (rhs))
- res_cmp = one_cmp == LT_EXPR ? GT_EXPR : LT_EXPR;
- else if (integer_onep (rhs))
- res_cmp = one_cmp;
- else
+ if (TREE_CODE (rhs) != INTEGER_CST)
return false;
- break;
- case NE_EXPR:
- if (integer_zerop (rhs))
- res_cmp = NE_EXPR;
- else if (integer_minus_onep (rhs))
- res_cmp = one_cmp == LT_EXPR ? LE_EXPR : GE_EXPR;
- else if (integer_onep (rhs))
- res_cmp = one_cmp == LT_EXPR ? GE_EXPR : LE_EXPR;
- else
- return false;
- break;
- case LT_EXPR:
- if (integer_onep (rhs))
- res_cmp = one_cmp == LT_EXPR ? GE_EXPR : LE_EXPR;
- else if (integer_zerop (rhs))
- res_cmp = one_cmp == LT_EXPR ? GT_EXPR : LT_EXPR;
- else
- return false;
- break;
- case LE_EXPR:
- if (integer_zerop (rhs))
- res_cmp = one_cmp == LT_EXPR ? GE_EXPR : LE_EXPR;
- else if (integer_minus_onep (rhs))
- res_cmp = one_cmp == LT_EXPR ? GT_EXPR : LT_EXPR;
- else
- return false;
- break;
- case GT_EXPR:
- if (integer_minus_onep (rhs))
- res_cmp = one_cmp == LT_EXPR ? LE_EXPR : GE_EXPR;
- else if (integer_zerop (rhs))
- res_cmp = one_cmp;
- else
- return false;
- break;
- case GE_EXPR:
- if (integer_zerop (rhs))
- res_cmp = one_cmp == LT_EXPR ? LE_EXPR : GE_EXPR;
- else if (integer_onep (rhs))
- res_cmp = one_cmp;
- else
- return false;
- break;
- default:
- gcc_unreachable ();
+ /* As for -ffast-math we assume the 2 return to be
+ impossible, canonicalize (unsigned) res <= 1U or
+ (unsigned) res < 2U into res >= 0 and (unsigned) res > 1U
+ or (unsigned) res >= 2U as res < 0. */
+ switch (cmp)
+ {
+ case LE_EXPR:
+ if (!integer_onep (rhs))
+ return false;
+ res_cmp = GE_EXPR;
+ break;
+ case LT_EXPR:
+ if (wi::ne_p (wi::to_widest (rhs), 2))
+ return false;
+ res_cmp = GE_EXPR;
+ break;
+ case GT_EXPR:
+ if (!integer_onep (rhs))
+ return false;
+ res_cmp = LT_EXPR;
+ break;
+ case GE_EXPR:
+ if (wi::ne_p (wi::to_widest (rhs), 2))
+ return false;
+ res_cmp = LT_EXPR;
+ break;
+ default:
+ return false;
+ }
+ rhs = build_zero_cst (TREE_TYPE (phires));
+ }
+ else
+ {
+ switch (cmp)
+ {
+ case EQ_EXPR:
+ if (integer_zerop (rhs))
+ res_cmp = EQ_EXPR;
+ else if (integer_minus_onep (rhs))
+ res_cmp = one_cmp == LT_EXPR ? GT_EXPR : LT_EXPR;
+ else if (integer_onep (rhs))
+ res_cmp = one_cmp;
+ else
+ return false;
+ break;
+ case NE_EXPR:
+ if (integer_zerop (rhs))
+ res_cmp = NE_EXPR;
+ else if (integer_minus_onep (rhs))
+ res_cmp = one_cmp == LT_EXPR ? LE_EXPR : GE_EXPR;
+ else if (integer_onep (rhs))
+ res_cmp = one_cmp == LT_EXPR ? GE_EXPR : LE_EXPR;
+ else
+ return false;
+ break;
+ case LT_EXPR:
+ if (integer_onep (rhs))
+ res_cmp = one_cmp == LT_EXPR ? GE_EXPR : LE_EXPR;
+ else if (integer_zerop (rhs))
+ res_cmp = one_cmp == LT_EXPR ? GT_EXPR : LT_EXPR;
+ else
+ return false;
+ break;
+ case LE_EXPR:
+ if (integer_zerop (rhs))
+ res_cmp = one_cmp == LT_EXPR ? GE_EXPR : LE_EXPR;
+ else if (integer_minus_onep (rhs))
+ res_cmp = one_cmp == LT_EXPR ? GT_EXPR : LT_EXPR;
+ else
+ return false;
+ break;
+ case GT_EXPR:
+ if (integer_minus_onep (rhs))
+ res_cmp = one_cmp == LT_EXPR ? LE_EXPR : GE_EXPR;
+ else if (integer_zerop (rhs))
+ res_cmp = one_cmp;
+ else
+ return false;
+ break;
+ case GE_EXPR:
+ if (integer_zerop (rhs))
+ res_cmp = one_cmp == LT_EXPR ? LE_EXPR : GE_EXPR;
+ else if (integer_onep (rhs))
+ res_cmp = one_cmp;
+ else
+ return false;
+ break;
+ default:
+ gcc_unreachable ();
+ }
}
if (gimple_code (use_stmt) == GIMPLE_COND)
@@ -2394,6 +2458,7 @@ spaceship_replacement (basic_block cond_bb, basic_block
middle_bb,
use_operand_p use_p;
imm_use_iterator iter;
bool has_debug_uses = false;
+ bool has_cast_debug_uses = false;
FOR_EACH_IMM_USE_FAST (use_p, iter, phires)
{
gimple *use_stmt = USE_STMT (use_p);
@@ -2405,12 +2470,14 @@ spaceship_replacement (basic_block cond_bb, basic_block
middle_bb,
}
if (orig_use_lhs)
{
- if (!has_debug_uses)
+ if (!has_debug_uses || is_cast)
FOR_EACH_IMM_USE_FAST (use_p, iter, orig_use_lhs)
{
gimple *use_stmt = USE_STMT (use_p);
gcc_assert (is_gimple_debug (use_stmt));
has_debug_uses = true;
+ if (is_cast)
+ has_cast_debug_uses = true;
}
gimple_stmt_iterator gsi = gsi_for_stmt (orig_use_stmt);
tree zero = build_zero_cst (TREE_TYPE (orig_use_lhs));
@@ -2448,7 +2515,23 @@ spaceship_replacement (basic_block cond_bb, basic_block
middle_bb,
gsi_insert_before (&gsi, g, GSI_SAME_STMT);
replace_uses_by (phires, temp2);
if (orig_use_lhs)
- replace_uses_by (orig_use_lhs, temp2);
+ {
+ if (has_cast_debug_uses)
+ {
+ tree temp3 = make_node (DEBUG_EXPR_DECL);
+ DECL_ARTIFICIAL (temp3) = 1;
+ TREE_TYPE (temp3) = TREE_TYPE (orig_use_lhs);
+ SET_DECL_MODE (temp3, TYPE_MODE (type));
+ t = build2 (EQ_EXPR, boolean_type_node, lhs1, rhs2);
+ t = build3 (COND_EXPR, type, t, build_zero_cst (type),
+ temp1);
+ g = gimple_build_debug_bind (temp3, t, phi);
+ gsi_insert_before (&gsi, g, GSI_SAME_STMT);
+ replace_uses_by (orig_use_lhs, temp3);
+ }
+ else
+ replace_uses_by (orig_use_lhs, temp2);
+ }
}
}
rb14938.patch
Description: rb14938.patch
