match.pd: Add new abs pattern [PR94920]
This patch is intended to fix a missed optimization in match.pd. It optimizes (x >= 0 ? x : 0) + (x <= 0 ? -x : 0) to just abs(x). Additionally, the pattern (x <= 0 ? -x : 0) now gets optimized to max(-x, 0), which helps with the other simplification rule. Tests are also included to be added to the testsuite. Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? PR tree-optimization/94920 gcc/ChangeLog: * match.pd (x >= 0 ? x : 0) + (x <= 0 ? -x : 0): New simplification. (x <= 0 ? -x : 0): New simplification. gcc/testsuite/ChangeLog: * g++.dg/pr94920-1.C: New test. * g++.dg/pr94920.C: New test. * gcc.dg/pr94920-2.c: New test.
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gcc/match.pd
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gcc/match.pd
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@ -339,6 +339,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
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(if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (@0)))
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(COPYSIGN_ALL (negate @0) @1)))
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/* (x >= 0 ? x : 0) + (x <= 0 ? -x : 0) -> abs x. */
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(simplify
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(plus:c (max @0 integer_zerop) (max (negate @0) integer_zerop))
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(abs @0))
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/* X * 1, X / 1 -> X. */
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(for op (mult trunc_div ceil_div floor_div round_div exact_div)
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(simplify
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@ -3425,6 +3430,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
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&& (GIMPLE || !TREE_SIDE_EFFECTS (@1)))
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(cond (convert:boolean_type_node @2) @1 @0)))
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/* (x <= 0 ? -x : 0) -> max(-x, 0). */
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(simplify
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(cond (le @0 integer_zerop@1) (negate@2 @0) integer_zerop@1)
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(max @2 @1))
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/* Simplifications of shift and rotates. */
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(for rotate (lrotate rrotate)
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@ -0,0 +1,17 @@
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/* PR tree-optimization/94920 */
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/* { dg-do run } */
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#include "pr94920.C"
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int main() {
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if (foo(0) != 0
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|| foo(-42) != 42
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|| foo(42) != 42
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|| baz(-10) != 10
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|| baz(-10) != 10) {
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__builtin_abort();
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}
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return 0;
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}
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@ -0,0 +1,63 @@
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/* PR tree-optimization/94920 */
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/* { dg-do compile } */
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/* { dg-options "-O2 -fdump-tree-optimized" } */
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typedef int __attribute__((vector_size(4*sizeof(int)))) vint;
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/* Same form as PR. */
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__attribute__((noipa)) unsigned int foo(int x) {
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return (x >= 0 ? x : 0) + (x <= 0 ? -x : 0);
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}
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/* Test for forward propogation. */
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__attribute__((noipa)) unsigned int corge(int x) {
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int w = (x >= 0 ? x : 0);
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int y = -x;
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int z = (y >= 0 ? y : 0);
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return w + z;
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}
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/* Vector case. */
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__attribute__((noipa)) vint thud(vint x) {
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vint t = (x >= 0 ? x : 0) ;
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vint xx = -x;
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vint t1 = (xx >= 0 ? xx : 0);
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return t + t1;
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}
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/* Signed function. */
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__attribute__((noipa)) int bar(int x) {
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return (x >= 0 ? x : 0) + (x <= 0 ? -x : 0);
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}
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/* Commutative property. */
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__attribute__((noipa)) unsigned int baz(int x) {
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return (x <= 0 ? -x : 0) + (x >= 0 ? x : 0);
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}
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/* Flipped order for max expressions. */
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__attribute__((noipa)) unsigned int quux(int x) {
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return (0 <= x ? x : 0) + (0 >= x ? -x : 0);
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}
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/* Not zero so should not optimize. */
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__attribute__((noipa)) unsigned int waldo(int x) {
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return (x >= 4 ? x : 4) + (x <= 4 ? -x : 4);
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}
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/* Not zero so should not optimize. */
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__attribute__((noipa)) unsigned int fred(int x) {
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return (x >= -4 ? x : -4) + (x <= -4 ? -x : -4);
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}
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/* Incorrect pattern. */
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__attribute__((noipa)) unsigned int goo(int x) {
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return (x <= 0 ? x : 0) + (x >= 0 ? -x : 0);
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}
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/* Incorrect pattern. */
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__attribute__((noipa)) int qux(int x) {
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return (x >= 0 ? x : 0) + (x >= 0 ? x : 0);
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}
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/* { dg-final {scan-tree-dump-times " ABS_EXPR " 6 "optimized" } } */
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@ -0,0 +1,15 @@
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/* PR tree-optimization/94920 */
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/* { dg-do compile } */
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/* { dg-options "-O2 -fdump-tree-optimized" } */
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/* Form from PR. */
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__attribute__((noipa)) unsigned int foo(int x) {
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return x <= 0 ? -x : 0;
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}
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/* Changed order. */
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__attribute__((noipa)) unsigned int bar(int x) {
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return 0 >= x ? -x : 0;
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}
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/* { dg-final {scan-tree-dump-times " MAX_EXPR " 2 "optimized" } } */
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