Re: [PATCH] tree-ssa-math-opts: Pattern recognize yet another .ADD_OVERFLOW pattern [PR113982]
On Mon, 13 May 2024, Jakub Jelinek wrote:
> Hi!
>
> We pattern recognize already many different patterns, and closest to the
> requested one also
>yc = (type) y;
>zc = (type) z;
>x = yc + zc;
>w = (typeof_y) x;
>if (x > max)
> where y/z has the same unsigned type and type is a wider unsigned type
> and max is maximum value of the narrower unsigned type.
> But apparently people are creative in writing this in diffent ways,
> this requests
>yc = (type) y;
>zc = (type) z;
>x = yc + zc;
>w = (typeof_y) x;
>if (x >> narrower_type_bits)
>
> The following patch implements that.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK. Seeing the large matching code I wonder if using a match
in match.pd might be more easy to maintain (eh, and I'd still
like to somehow see "inline" match patterns in source files, not
sure how, but requiring some gen* program extracting them).
Thanks,
Richard.
> 2024-05-13 Jakub Jelinek
>
> PR middle-end/113982
> * tree-ssa-math-opts.cc (arith_overflow_check_p): Also return 1
> for RSHIFT_EXPR by precision of maxval if shift result is only
> used in a cast or comparison against zero.
> (match_arith_overflow): Handle the RSHIFT_EXPR use case.
>
> * gcc.dg/pr113982.c: New test.
>
> --- gcc/tree-ssa-math-opts.cc.jj 2024-04-11 09:26:36.318369218 +0200
> +++ gcc/tree-ssa-math-opts.cc 2024-05-10 18:17:08.795744811 +0200
> @@ -3947,6 +3947,66 @@ arith_overflow_check_p (gimple *stmt, gi
>else
> return 0;
>
> + if (maxval
> + && ccode == RSHIFT_EXPR
> + && crhs1 == lhs
> + && TREE_CODE (crhs2) == INTEGER_CST
> + && wi::to_widest (crhs2) == TYPE_PRECISION (TREE_TYPE (maxval)))
> +{
> + tree shiftlhs = gimple_assign_lhs (use_stmt);
> + if (!shiftlhs)
> + return 0;
> + use_operand_p use;
> + if (!single_imm_use (shiftlhs, , _use_stmt))
> + return 0;
> + if (gimple_code (cur_use_stmt) == GIMPLE_COND)
> + {
> + ccode = gimple_cond_code (cur_use_stmt);
> + crhs1 = gimple_cond_lhs (cur_use_stmt);
> + crhs2 = gimple_cond_rhs (cur_use_stmt);
> + }
> + else if (is_gimple_assign (cur_use_stmt))
> + {
> + if (gimple_assign_rhs_class (cur_use_stmt) == GIMPLE_BINARY_RHS)
> + {
> + ccode = gimple_assign_rhs_code (cur_use_stmt);
> + crhs1 = gimple_assign_rhs1 (cur_use_stmt);
> + crhs2 = gimple_assign_rhs2 (cur_use_stmt);
> + }
> + else if (gimple_assign_rhs_code (cur_use_stmt) == COND_EXPR)
> + {
> + tree cond = gimple_assign_rhs1 (cur_use_stmt);
> + if (COMPARISON_CLASS_P (cond))
> + {
> + ccode = TREE_CODE (cond);
> + crhs1 = TREE_OPERAND (cond, 0);
> + crhs2 = TREE_OPERAND (cond, 1);
> + }
> + else
> + return 0;
> + }
> + else
> + {
> + enum tree_code sc = gimple_assign_rhs_code (cur_use_stmt);
> + tree castlhs = gimple_assign_lhs (cur_use_stmt);
> + if (!CONVERT_EXPR_CODE_P (sc)
> + || !castlhs
> + || !INTEGRAL_TYPE_P (TREE_TYPE (castlhs))
> + || (TYPE_PRECISION (TREE_TYPE (castlhs))
> + > TYPE_PRECISION (TREE_TYPE (maxval
> + return 0;
> + return 1;
> + }
> + }
> + else
> + return 0;
> + if ((ccode != EQ_EXPR && ccode != NE_EXPR)
> + || crhs1 != shiftlhs
> + || !integer_zerop (crhs2))
> + return 0;
> + return 1;
> +}
> +
>if (TREE_CODE_CLASS (ccode) != tcc_comparison)
> return 0;
>
> @@ -4049,6 +4109,7 @@ arith_overflow_check_p (gimple *stmt, gi
> _8 = IMAGPART_EXPR <_7>;
> if (_8)
> and replace (utype) x with _9.
> + Or with x >> popcount (max) instead of x > max.
>
> Also recognize:
> x = ~z;
> @@ -4481,10 +4542,62 @@ match_arith_overflow (gimple_stmt_iterat
> gcc_checking_assert (is_gimple_assign (use_stmt));
> if (gimple_assign_rhs_class (use_stmt) == GIMPLE_BINARY_RHS)
> {
> - gimple_assign_set_rhs1 (use_stmt, ovf);
> - gimple_assign_set_rhs2 (use_stmt, build_int_cst (type, 0));
> - gimple_assign_set_rhs_code (use_stmt,
> - ovf_use == 1 ? NE_EXPR : EQ_EXPR);
> + if (gimple_assign_rhs_code (use_stmt) == RSHIFT_EXPR)
> + {
> + g2 = gimple_build_assign (make_ssa_name (boolean_type_node),
> + ovf_use == 1 ? NE_EXPR : EQ_EXPR,
> + ovf, build_int_cst (type, 0));
> + gimple_stmt_iterator gsiu = gsi_for_stmt (use_stmt);
> + gsi_insert_before (, g2, GSI_SAME_STMT);
> + gimple_assign_set_rhs_with_ops (, NOP_EXPR,
> +
[PATCH] tree-ssa-math-opts: Pattern recognize yet another .ADD_OVERFLOW pattern [PR113982]
Hi!
We pattern recognize already many different patterns, and closest to the
requested one also
yc = (type) y;
zc = (type) z;
x = yc + zc;
w = (typeof_y) x;
if (x > max)
where y/z has the same unsigned type and type is a wider unsigned type
and max is maximum value of the narrower unsigned type.
But apparently people are creative in writing this in diffent ways,
this requests
yc = (type) y;
zc = (type) z;
x = yc + zc;
w = (typeof_y) x;
if (x >> narrower_type_bits)
The following patch implements that.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2024-05-13 Jakub Jelinek
PR middle-end/113982
* tree-ssa-math-opts.cc (arith_overflow_check_p): Also return 1
for RSHIFT_EXPR by precision of maxval if shift result is only
used in a cast or comparison against zero.
(match_arith_overflow): Handle the RSHIFT_EXPR use case.
* gcc.dg/pr113982.c: New test.
--- gcc/tree-ssa-math-opts.cc.jj2024-04-11 09:26:36.318369218 +0200
+++ gcc/tree-ssa-math-opts.cc 2024-05-10 18:17:08.795744811 +0200
@@ -3947,6 +3947,66 @@ arith_overflow_check_p (gimple *stmt, gi
else
return 0;
+ if (maxval
+ && ccode == RSHIFT_EXPR
+ && crhs1 == lhs
+ && TREE_CODE (crhs2) == INTEGER_CST
+ && wi::to_widest (crhs2) == TYPE_PRECISION (TREE_TYPE (maxval)))
+{
+ tree shiftlhs = gimple_assign_lhs (use_stmt);
+ if (!shiftlhs)
+ return 0;
+ use_operand_p use;
+ if (!single_imm_use (shiftlhs, , _use_stmt))
+ return 0;
+ if (gimple_code (cur_use_stmt) == GIMPLE_COND)
+ {
+ ccode = gimple_cond_code (cur_use_stmt);
+ crhs1 = gimple_cond_lhs (cur_use_stmt);
+ crhs2 = gimple_cond_rhs (cur_use_stmt);
+ }
+ else if (is_gimple_assign (cur_use_stmt))
+ {
+ if (gimple_assign_rhs_class (cur_use_stmt) == GIMPLE_BINARY_RHS)
+ {
+ ccode = gimple_assign_rhs_code (cur_use_stmt);
+ crhs1 = gimple_assign_rhs1 (cur_use_stmt);
+ crhs2 = gimple_assign_rhs2 (cur_use_stmt);
+ }
+ else if (gimple_assign_rhs_code (cur_use_stmt) == COND_EXPR)
+ {
+ tree cond = gimple_assign_rhs1 (cur_use_stmt);
+ if (COMPARISON_CLASS_P (cond))
+ {
+ ccode = TREE_CODE (cond);
+ crhs1 = TREE_OPERAND (cond, 0);
+ crhs2 = TREE_OPERAND (cond, 1);
+ }
+ else
+ return 0;
+ }
+ else
+ {
+ enum tree_code sc = gimple_assign_rhs_code (cur_use_stmt);
+ tree castlhs = gimple_assign_lhs (cur_use_stmt);
+ if (!CONVERT_EXPR_CODE_P (sc)
+ || !castlhs
+ || !INTEGRAL_TYPE_P (TREE_TYPE (castlhs))
+ || (TYPE_PRECISION (TREE_TYPE (castlhs))
+ > TYPE_PRECISION (TREE_TYPE (maxval
+ return 0;
+ return 1;
+ }
+ }
+ else
+ return 0;
+ if ((ccode != EQ_EXPR && ccode != NE_EXPR)
+ || crhs1 != shiftlhs
+ || !integer_zerop (crhs2))
+ return 0;
+ return 1;
+}
+
if (TREE_CODE_CLASS (ccode) != tcc_comparison)
return 0;
@@ -4049,6 +4109,7 @@ arith_overflow_check_p (gimple *stmt, gi
_8 = IMAGPART_EXPR <_7>;
if (_8)
and replace (utype) x with _9.
+ Or with x >> popcount (max) instead of x > max.
Also recognize:
x = ~z;
@@ -4481,10 +4542,62 @@ match_arith_overflow (gimple_stmt_iterat
gcc_checking_assert (is_gimple_assign (use_stmt));
if (gimple_assign_rhs_class (use_stmt) == GIMPLE_BINARY_RHS)
{
- gimple_assign_set_rhs1 (use_stmt, ovf);
- gimple_assign_set_rhs2 (use_stmt, build_int_cst (type, 0));
- gimple_assign_set_rhs_code (use_stmt,
- ovf_use == 1 ? NE_EXPR : EQ_EXPR);
+ if (gimple_assign_rhs_code (use_stmt) == RSHIFT_EXPR)
+ {
+ g2 = gimple_build_assign (make_ssa_name (boolean_type_node),
+ ovf_use == 1 ? NE_EXPR : EQ_EXPR,
+ ovf, build_int_cst (type, 0));
+ gimple_stmt_iterator gsiu = gsi_for_stmt (use_stmt);
+ gsi_insert_before (, g2, GSI_SAME_STMT);
+ gimple_assign_set_rhs_with_ops (, NOP_EXPR,
+ gimple_assign_lhs (g2));
+ update_stmt (use_stmt);
+ use_operand_p use;
+ single_imm_use (gimple_assign_lhs (use_stmt), ,
+ _stmt);
+ if (gimple_code (use_stmt) == GIMPLE_COND)
+ {
+ gcond *cond_stmt = as_a (use_stmt);
+ gimple_cond_set_lhs (cond_stmt, ovf);
+
