From e7b22f97f960b62e555dfd6f2e3ae43973fcbb3e Mon Sep 17 00:00:00 2001
From: Pronin Alexander 00812787 <pronin.alexander@huawei.com>
Date: Wed, 25 Jan 2023 15:04:07 +0300
Subject: [PATCH 05/18] Match double sized mul pattern
---
gcc/match.pd | 136 +++++++++++++++++++++
gcc/testsuite/gcc.dg/double_sized_mul-1.c | 141 ++++++++++++++++++++++
gcc/testsuite/gcc.dg/double_sized_mul-2.c | 62 ++++++++++
gcc/tree-ssa-math-opts.cc | 80 ++++++++++++
4 files changed, 419 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/double_sized_mul-1.c
create mode 100644 gcc/testsuite/gcc.dg/double_sized_mul-2.c
diff --git a/gcc/match.pd b/gcc/match.pd
index 3cbaf2a5b..61866cb90 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -7895,3 +7895,139 @@ and,
== TYPE_UNSIGNED (TREE_TYPE (@3))))
&& single_use (@4)
&& single_use (@5))))
+
+/* Match multiplication with double sized result.
+
+ Consider the following calculations:
+ arg0 * arg1 = (2^(bit_size/2) * arg0_hi + arg0_lo)
+ * (2^(bit_size/2) * arg1_hi + arg1_lo)
+ arg0 * arg1 = 2^bit_size * arg0_hi * arg1_hi
+ + 2^(bit_size/2) * (arg0_hi * arg1_lo + arg0_lo * arg1_hi)
+ + arg0_lo * arg1_lo
+
+ The products of high and low parts fits in bit_size values, thus they are
+ placed in high and low parts of result respectively.
+
+ The sum of the mixed products may overflow, so we need a detection for that.
+ Also it has a bit_size/2 offset, thus it intersects with both high and low
+ parts of result. Overflow detection constant is bit_size/2 due to this.
+
+ With this info:
+ arg0 * arg1 = 2^bit_size * arg0_hi * arg1_hi
+ + 2^(bit_size/2) * middle
+ + 2^bit_size * possible_middle_overflow
+ + arg0_lo * arg1_lo
+ arg0 * arg1 = 2^bit_size * (arg0_hi * arg1_hi + possible_middle_overflow)
+ + 2^(bit_size/2) * (2^(bit_size/2) * middle_hi + middle_lo)
+ + arg0_lo * arg1_lo
+ arg0 * arg1 = 2^bit_size * (arg0_hi * arg1_hi + middle_hi
+ + possible_middle_overflow)
+ + 2^(bit_size/2) * middle_lo
+ + arg0_lo * arg1_lo
+
+ The last sum can produce overflow for the high result part. With this:
+ arg0 * arg1 = 2^bit_size * (arg0_hi * arg1_hi + possible_middle_overflow
+ + possible_res_lo_overflow + middle_hi)
+ + res_lo
+ = res_hi + res_lo
+
+ This formula is quite big to fit into one match pattern with all of the
+ combinations of terms inside it. There are many helpers for better code
+ readability.
+
+ The simplification basis is res_hi: assuming that res_lo only is not
+ real practical case for such calculations.
+
+ Overflow handling is done via matching complex calculations:
+ the realpart and imagpart are quite handy here. */
+/* Match low and high parts of the argument. */
+(match (double_size_mul_arg_lo @0 @1)
+ (bit_and @0 INTEGER_CST@1)
+ (if (wi::to_wide (@1)
+ == wi::mask (TYPE_PRECISION (type) / 2, false, TYPE_PRECISION (type)))))
+(match (double_size_mul_arg_hi @0 @1)
+ (rshift @0 INTEGER_CST@1)
+ (if (wi::to_wide (@1) == TYPE_PRECISION (type) / 2)))
+
+/* Match various argument parts products. */
+(match (double_size_mul_lolo @0 @1)
+ (mult@4 (double_size_mul_arg_lo @0 @2) (double_size_mul_arg_lo @1 @3))
+ (if (single_use (@4))))
+(match (double_size_mul_hihi @0 @1)
+ (mult@4 (double_size_mul_arg_hi @0 @2) (double_size_mul_arg_hi @1 @3))
+ (if (single_use (@4))))
+(match (double_size_mul_lohi @0 @1)
+ (mult:c@4 (double_size_mul_arg_lo @0 @2) (double_size_mul_arg_hi @1 @3))
+ (if (single_use (@4))))
+
+/* Match complex middle sum. */
+(match (double_size_mul_middle_complex @0 @1)
+ (IFN_ADD_OVERFLOW@2 (double_size_mul_lohi @0 @1) (double_size_mul_lohi @1 @0))
+ (if (num_imm_uses (@2) == 2)))
+
+/* Match real middle results. */
+(match (double_size_mul_middle @0 @1)
+ (realpart@2 (double_size_mul_middle_complex @0 @1))
+ (if (num_imm_uses (@2) == 2)))
+(match (double_size_mul_middleres_lo @0 @1)
+ (lshift@3 (double_size_mul_middle @0 @1) INTEGER_CST@2)
+ (if (wi::to_wide (@2) == TYPE_PRECISION (type) / 2
+ && single_use (@3))))
+(match (double_size_mul_middleres_hi @0 @1)
+ (rshift@3 (double_size_mul_middle @0 @1) INTEGER_CST@2)
+ (if (wi::to_wide (@2) == TYPE_PRECISION (type) / 2
+ && single_use (@3))))
+
+/* Match low result part. */
+/* Number of uses may be < 2 in case when we are interested in
+ high part only. */
+(match (double_size_mul_res_lo_complex @0 @1)
+ (IFN_ADD_OVERFLOW:c@2
+ (double_size_mul_lolo:c @0 @1) (double_size_mul_middleres_lo @0 @1))
+ (if (num_imm_uses (@2) <= 2)))
+(match (double_size_mul_res_lo @0 @1)
+ (realpart (double_size_mul_res_lo_complex @0 @1)))
+
+/* Match overflow terms. */
+(match (double_size_mul_overflow_check_lo @0 @1 @5)
+ (convert@4 (ne@3
+ (imagpart@2 (double_size_mul_res_lo_complex@5 @0 @1)) integer_zerop))
+ (if (single_use (@2) && single_use (@3) && single_use (@4))))
+(match (double_size_mul_overflow_check_hi @0 @1)
+ (lshift@6 (convert@5 (ne@4
+ (imagpart@3 (double_size_mul_middle_complex @0 @1)) integer_zerop))
+ INTEGER_CST@2)
+ (if (wi::to_wide (@2) == TYPE_PRECISION (type) / 2
+ && single_use (@3) && single_use (@4) && single_use (@5)
+ && single_use (@6))))
+
+/* Match all possible permutations for high result part calculations. */
+(for op1 (double_size_mul_hihi
+ double_size_mul_overflow_check_hi
+ double_size_mul_middleres_hi)
+ op2 (double_size_mul_overflow_check_hi
+ double_size_mul_middleres_hi
+ double_size_mul_hihi)
+ op3 (double_size_mul_middleres_hi
+ double_size_mul_hihi
+ double_size_mul_overflow_check_hi)
+ (match (double_size_mul_candidate @0 @1 @2 @3)
+ (plus:c@2
+ (plus:c@4 (double_size_mul_overflow_check_lo @0 @1 @3) (op1:c @0 @1))
+ (plus:c@5 (op2:c @0 @1) (op3:c @0 @1)))
+ (if (single_use (@4) && single_use (@5))))
+ (match (double_size_mul_candidate @0 @1 @2 @3)
+ (plus:c@2 (double_size_mul_overflow_check_lo @0 @1 @3)
+ (plus:c@4 (op1:c @0 @1)
+ (plus:c@5 (op2:c @0 @1) (op3:c @0 @1))))
+ (if (single_use (@4) && single_use (@5))))
+ (match (double_size_mul_candidate @0 @1 @2 @3)
+ (plus:c@2 (op1:c @0 @1)
+ (plus:c@4 (double_size_mul_overflow_check_lo @0 @1 @3)
+ (plus:c@5 (op2:c @0 @1) (op3:c @0 @1))))
+ (if (single_use (@4) && single_use (@5))))
+ (match (double_size_mul_candidate @0 @1 @2 @3)
+ (plus:c@2 (op1:c @0 @1)
+ (plus:c@4 (op2:c @0 @1)
+ (plus:c@5 (double_size_mul_overflow_check_lo @0 @1 @3) (op3:c @0 @1))))
+ (if (single_use (@4) && single_use (@5)))))
diff --git a/gcc/testsuite/gcc.dg/double_sized_mul-1.c b/gcc/testsuite/gcc.dg/double_sized_mul-1.c
new file mode 100644
index 000000000..4d475cc8a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/double_sized_mul-1.c
@@ -0,0 +1,141 @@
+/* { dg-do compile } */
+/* fif-conversion-gimple and fuaddsub-overflow-match-all are required for
+ proper overflow detection in some cases. */
+/* { dg-options "-O2 -fif-conversion-gimple -fuaddsub-overflow-match-all -fdump-tree-widening_mul-stats" } */
+#include <stdint.h>
+
+typedef unsigned __int128 uint128_t;
+
+uint16_t mul16 (uint8_t a, uint8_t b)
+{
+ uint8_t a_lo = a & 0xF;
+ uint8_t b_lo = b & 0xF;
+ uint8_t a_hi = a >> 4;
+ uint8_t b_hi = b >> 4;
+ uint8_t lolo = a_lo * b_lo;
+ uint8_t lohi = a_lo * b_hi;
+ uint8_t hilo = a_hi * b_lo;
+ uint8_t hihi = a_hi * b_hi;
+ uint8_t middle = hilo + lohi;
+ uint8_t middle_hi = middle >> 4;
+ uint8_t middle_lo = middle << 4;
+ uint8_t res_lo = lolo + middle_lo;
+ uint8_t res_hi = hihi + middle_hi;
+ res_hi += (res_lo < middle_lo ? 1 : 0);
+ res_hi += (middle < hilo ? 0x10 : 0);
+ uint16_t res = ((uint16_t) res_hi) << 8;
+ res += res_lo;
+ return res;
+}
+
+uint32_t mul32 (uint16_t a, uint16_t b)
+{
+ uint16_t a_lo = a & 0xFF;
+ uint16_t b_lo = b & 0xFF;
+ uint16_t a_hi = a >> 8;
+ uint16_t b_hi = b >> 8;
+ uint16_t lolo = a_lo * b_lo;
+ uint16_t lohi = a_lo * b_hi;
+ uint16_t hilo = a_hi * b_lo;
+ uint16_t hihi = a_hi * b_hi;
+ uint16_t middle = hilo + lohi;
+ uint16_t middle_hi = middle >> 8;
+ uint16_t middle_lo = middle << 8;
+ uint16_t res_lo = lolo + middle_lo;
+ uint16_t res_hi = hihi + middle_hi;
+ res_hi += (res_lo < middle_lo ? 1 : 0);
+ res_hi += (middle < hilo ? 0x100 : 0);
+ uint32_t res = ((uint32_t) res_hi) << 16;
+ res += res_lo;
+ return res;
+}
+
+uint64_t mul64 (uint32_t a, uint32_t b)
+{
+ uint32_t a_lo = a & 0xFFFF;
+ uint32_t b_lo = b & 0xFFFF;
+ uint32_t a_hi = a >> 16;
+ uint32_t b_hi = b >> 16;
+ uint32_t lolo = a_lo * b_lo;
+ uint32_t lohi = a_lo * b_hi;
+ uint32_t hilo = a_hi * b_lo;
+ uint32_t hihi = a_hi * b_hi;
+ uint32_t middle = hilo + lohi;
+ uint32_t middle_hi = middle >> 16;
+ uint32_t middle_lo = middle << 16;
+ uint32_t res_lo = lolo + middle_lo;
+ uint32_t res_hi = hihi + middle_hi;
+ res_hi += (res_lo < middle_lo ? 1 : 0);
+ res_hi += (middle < hilo ? 0x10000 : 0);
+ uint64_t res = ((uint64_t) res_hi) << 32;
+ res += res_lo;
+ return res;
+}
+
+uint128_t mul128 (uint64_t a, uint64_t b)
+{
+ uint64_t a_lo = a & 0xFFFFFFFF;
+ uint64_t b_lo = b & 0xFFFFFFFF;
+ uint64_t a_hi = a >> 32;
+ uint64_t b_hi = b >> 32;
+ uint64_t lolo = a_lo * b_lo;
+ uint64_t lohi = a_lo * b_hi;
+ uint64_t hilo = a_hi * b_lo;
+ uint64_t hihi = a_hi * b_hi;
+ uint64_t middle = hilo + lohi;
+ uint64_t middle_hi = middle >> 32;
+ uint64_t middle_lo = middle << 32;
+ uint64_t res_lo = lolo + middle_lo;
+ uint64_t res_hi = hihi + middle_hi;
+ res_hi += (res_lo < middle_lo ? 1 : 0);
+ res_hi += (middle < hilo ? 0x100000000 : 0);
+ uint128_t res = ((uint128_t) res_hi) << 64;
+ res += res_lo;
+ return res;
+}
+
+uint64_t mul64_perm (uint32_t a, uint32_t b)
+{
+ uint32_t a_lo = a & 0xFFFF;
+ uint32_t b_lo = b & 0xFFFF;
+ uint32_t a_hi = a >> 16;
+ uint32_t b_hi = b >> 16;
+ uint32_t lolo = a_lo * b_lo;
+ uint32_t lohi = a_lo * b_hi;
+ uint32_t hilo = a_hi * b_lo;
+ uint32_t hihi = a_hi * b_hi;
+ uint32_t middle = hilo + lohi;
+ uint32_t middle_hi = middle >> 16;
+ uint32_t middle_lo = middle << 16;
+ uint32_t res_lo = lolo + middle_lo;
+ uint32_t res_hi = hihi + middle_hi;
+ res_hi = res_lo < middle_lo ? res_hi + 1 : res_hi;
+ res_hi = middle < hilo ? res_hi + 0x10000 : res_hi;
+ uint64_t res = ((uint64_t) res_hi) << 32;
+ res += res_lo;
+ return res;
+}
+
+uint128_t mul128_perm (uint64_t a, uint64_t b)
+{
+ uint64_t a_lo = a & 0xFFFFFFFF;
+ uint64_t b_lo = b & 0xFFFFFFFF;
+ uint64_t a_hi = a >> 32;
+ uint64_t b_hi = b >> 32;
+ uint64_t lolo = a_lo * b_lo;
+ uint64_t lohi = a_lo * b_hi;
+ uint64_t hilo = a_hi * b_lo;
+ uint64_t hihi = a_hi * b_hi;
+ uint64_t middle = hilo + lohi;
+ uint64_t middle_hi = middle >> 32;
+ uint64_t middle_lo = middle << 32;
+ uint64_t res_lo = lolo + middle_lo;
+ uint64_t res_hi = hihi + middle_hi;
+ res_hi = res_lo < middle_lo ? res_hi + 1 : res_hi;
+ res_hi = middle < hilo ? res_hi + 0x100000000 : res_hi;
+ uint128_t res = ((uint128_t) res_hi) << 64;
+ res += res_lo;
+ return res;
+}
+
+/* { dg-final { scan-tree-dump-times "double sized mul optimized: 1" 6 "widening_mul" } } */
diff --git a/gcc/testsuite/gcc.dg/double_sized_mul-2.c b/gcc/testsuite/gcc.dg/double_sized_mul-2.c
new file mode 100644
index 000000000..cc6e5af25
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/double_sized_mul-2.c
@@ -0,0 +1,62 @@
+/* { dg-do compile } */
+/* fif-conversion-gimple is required for proper overflow detection
+ in some cases. */
+/* { dg-options "-O2 -fif-conversion-gimple -fuaddsub-overflow-match-all -fdump-tree-widening_mul-stats" } */
+#include <stdint.h>
+
+typedef unsigned __int128 uint128_t;
+typedef struct uint256_t
+{
+ uint128_t lo;
+ uint128_t hi;
+} uint256_t;
+
+uint64_t mul64_double_use (uint32_t a, uint32_t b)
+{
+ uint32_t a_lo = a & 0xFFFF;
+ uint32_t b_lo = b & 0xFFFF;
+ uint32_t a_hi = a >> 16;
+ uint32_t b_hi = b >> 16;
+ uint32_t lolo = a_lo * b_lo;
+ uint32_t lohi = a_lo * b_hi;
+ uint32_t hilo = a_hi * b_lo;
+ uint32_t hihi = a_hi * b_hi;
+ uint32_t middle = hilo + lohi;
+ uint32_t middle_hi = middle >> 16;
+ uint32_t middle_lo = middle << 16;
+ uint32_t res_lo = lolo + middle_lo;
+ uint32_t res_hi = hihi + middle_hi;
+ res_hi += (res_lo < middle_lo ? 1 : 0);
+ res_hi += (middle < hilo ? 0x10000 : 0);
+ uint64_t res = ((uint64_t) res_hi) << 32;
+ res += res_lo;
+ return res + lolo;
+}
+
+uint256_t mul256 (uint128_t a, uint128_t b)
+{
+ uint128_t a_lo = a & 0xFFFFFFFFFFFFFFFF;
+ uint128_t b_lo = b & 0xFFFFFFFFFFFFFFFF;
+ uint128_t a_hi = a >> 64;
+ uint128_t b_hi = b >> 64;
+ uint128_t lolo = a_lo * b_lo;
+ uint128_t lohi = a_lo * b_hi;
+ uint128_t hilo = a_hi * b_lo;
+ uint128_t hihi = a_hi * b_hi;
+ uint128_t middle = hilo + lohi;
+ uint128_t middle_hi = middle >> 64;
+ uint128_t middle_lo = middle << 64;
+ uint128_t res_lo = lolo + middle_lo;
+ uint128_t res_hi = hihi + middle_hi;
+ res_hi += (res_lo < middle_lo ? 1 : 0);
+ /* Constant is to big warning WA */
+ uint128_t overflow_tmp = (middle < hilo ? 1 : 0);
+ overflow_tmp <<= 64;
+ res_hi += overflow_tmp;
+ uint256_t res;
+ res.lo = res_lo;
+ res.hi = res_hi;
+ return res;
+}
+
+/* { dg-final { scan-tree-dump-not "double sized mul optimized" "widening_mul" } } */
diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index 55d6ee8ae..2c06b8a60 100644
--- a/gcc/tree-ssa-math-opts.cc
+++ b/gcc/tree-ssa-math-opts.cc
@@ -210,6 +210,9 @@ static struct
/* Number of highpart multiplication ops inserted. */
int highpart_mults_inserted;
+
+ /* Number of optimized double sized multiplications. */
+ int double_sized_mul_optimized;
} widen_mul_stats;
/* The instance of "struct occurrence" representing the highest
@@ -4893,6 +4896,78 @@ optimize_spaceship (gimple *stmt)
}
+/* Pattern matcher for double sized multiplication defined in match.pd. */
+extern bool gimple_double_size_mul_candidate (tree, tree*, tree (*)(tree));
+
+static bool
+convert_double_size_mul (gimple_stmt_iterator *gsi, gimple *stmt)
+{
+ gimple *use_stmt, *complex_res_lo;
+ gimple_stmt_iterator insert_before;
+ imm_use_iterator use_iter;
+ tree match[4]; // arg0, arg1, res_hi, complex_res_lo
+ tree arg0, arg1, widen_mult, new_type, tmp;
+ tree lhs = gimple_assign_lhs (stmt);
+ location_t loc = UNKNOWN_LOCATION;
+ machine_mode mode;
+
+ if (!gimple_double_size_mul_candidate (lhs, match, NULL))
+ return false;
+
+ new_type = build_nonstandard_integer_type (
+ TYPE_PRECISION (TREE_TYPE (match[0])) * 2, 1);
+ mode = TYPE_MODE (new_type);
+
+ /* Early return if the target multiplication doesn't exist on target. */
+ if (optab_handler (smul_optab, mode) == CODE_FOR_nothing
+ && !wider_optab_check_p (smul_optab, mode, 1))
+ return false;
+
+ /* Determine the point where the wide multiplication
+ should be inserted. Complex low res is OK since it is required
+ by both high and low part getters, thus it dominates both of them. */
+ complex_res_lo = SSA_NAME_DEF_STMT (match[3]);
+ insert_before = gsi_for_stmt (complex_res_lo);
+ gsi_next (&insert_before);
+
+ /* Create the widen multiplication. */
+ arg0 = build_and_insert_cast (&insert_before, loc, new_type, match[0]);
+ arg1 = build_and_insert_cast (&insert_before, loc, new_type, match[1]);
+ widen_mult = build_and_insert_binop (&insert_before, loc, "widen_mult",
+ MULT_EXPR, arg0, arg1);
+
+ /* Find the mult low part getter. */
+ FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, match[3])
+ if (gimple_assign_rhs_code (use_stmt) == REALPART_EXPR)
+ break;
+
+ /* Create high and low (if needed) parts extractors. */
+ /* Low part. */
+ if (use_stmt)
+ {
+ loc = gimple_location (use_stmt);
+ tmp = build_and_insert_cast (&insert_before, loc,
+ TREE_TYPE (gimple_get_lhs (use_stmt)),
+ widen_mult);
+ gassign *new_stmt = gimple_build_assign (gimple_get_lhs (use_stmt),
+ NOP_EXPR, tmp);
+ gsi_replace (&insert_before, new_stmt, true);
+ }
+
+ /* High part. */
+ loc = gimple_location (stmt);
+ tmp = build_and_insert_binop (gsi, loc, "widen_mult_hi",
+ RSHIFT_EXPR, widen_mult,
+ build_int_cst (new_type,
+ TYPE_PRECISION (new_type) / 2));
+ tmp = build_and_insert_cast (gsi, loc, TREE_TYPE (lhs), tmp);
+ gassign *new_stmt = gimple_build_assign (lhs, NOP_EXPR, tmp);
+ gsi_replace (gsi, new_stmt, true);
+
+ widen_mul_stats.double_sized_mul_optimized++;
+ return true;
+}
+
/* Find integer multiplications where the operands are extended from
smaller types, and replace the MULT_EXPR with a WIDEN_MULT_EXPR
or MULT_HIGHPART_EXPR where appropriate. */
@@ -4987,6 +5062,9 @@ math_opts_dom_walker::after_dom_children (basic_block bb)
break;
case PLUS_EXPR:
+ if (convert_double_size_mul (&gsi, stmt))
+ break;
+ __attribute__ ((fallthrough));
case MINUS_EXPR:
if (!convert_plusminus_to_widen (&gsi, stmt, code))
match_arith_overflow (&gsi, stmt, code, m_cfg_changed_p);
@@ -5091,6 +5169,8 @@ pass_optimize_widening_mul::execute (function *fun)
widen_mul_stats.divmod_calls_inserted);
statistics_counter_event (fun, "highpart multiplications inserted",
widen_mul_stats.highpart_mults_inserted);
+ statistics_counter_event (fun, "double sized mul optimized",
+ widen_mul_stats.double_sized_mul_optimized);
return cfg_changed ? TODO_cleanup_cfg : 0;
}
--
2.33.0