https://gcc.gnu.org/g:c5ccdfdcab0b24afba2a661af861bec1d63f0595
commit r15-2637-gc5ccdfdcab0b24afba2a661af861bec1d63f0595 Author: Andrew Pinski <quic_apin...@quicinc.com> Date: Mon Jul 29 14:00:13 2024 -0700 match: Fix wrong code due to `(a ? e : f) !=/== (b ? e : f)` patterns [PR116120] When this pattern was converted from being only dealing with 0/-1, we missed that if `e == f` is true then the optimization is wrong and needs an extra check for that. This changes the patterns to be: /* (a ? x : y) != (b ? x : y) --> (a^b & (x != y)) ? TRUE : FALSE */ /* (a ? x : y) == (b ? x : y) --> (a^b & (x != y)) ? FALSE : TRUE */ /* (a ? x : y) != (b ? y : x) --> (a^b | (x == y)) ? FALSE : TRUE */ /* (a ? x : y) == (b ? y : x) --> (a^b | (x == y)) ? TRUE : FALSE */ Also this can't be done if the X can be a NaNs either. Since that changes the value there too. This still produces better code than the original case and in many cases (x != y) will still reduce to either false or true. With this change we also need to make sure `a`, `b` and the resulting types are all the same for the same reason as the previous patch. I updated (well added) to the testcases to make sure there are the right amount of comparisons left. Changes since v1: * v2: Fixed the testcase names and fixed dg-run to be `dg-do run`. Added a check for HONORS_NANS too. Bootstrapped and tested on x86_64-linux-gnu with no regressions. PR tree-optimization/116120 gcc/ChangeLog: * match.pd (`(a ? x : y) eq/ne (b ? x : y)`): Add test for `x != y` in result. (`(a ? x : y) eq/ne (b ? y : x)`): Add test for `x == y` in result. gcc/testsuite/ChangeLog: * g++.dg/tree-ssa/pr111150.C: Add extra checks on the test. * gcc.dg/tree-ssa/pr111150-1.c: Likewise. * gcc.dg/tree-ssa/pr111150.c: Likewise. * g++.dg/torture/pr116120-1.C: New test. * g++.dg/torture/pr116120-2.C: New test. Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com> Diff: --- gcc/match.pd | 23 ++++++++----- gcc/testsuite/g++.dg/torture/pr116120-1.C | 32 ++++++++++++++++++ gcc/testsuite/g++.dg/torture/pr116120-2.C | 53 ++++++++++++++++++++++++++++++ gcc/testsuite/g++.dg/tree-ssa/pr111150.C | 10 ++++++ gcc/testsuite/gcc.dg/tree-ssa/pr111150-1.c | 9 +++++ gcc/testsuite/gcc.dg/tree-ssa/pr111150.c | 1 + 6 files changed, 120 insertions(+), 8 deletions(-) diff --git a/gcc/match.pd b/gcc/match.pd index 881a827860f0..c9c8478d2865 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -5632,21 +5632,28 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (vec_cond (bit_and (bit_not @0) @1) @2 @3))) #endif -/* (a ? x : y) != (b ? x : y) --> (a^b) ? TRUE : FALSE */ -/* (a ? x : y) == (b ? x : y) --> (a^b) ? FALSE : TRUE */ -/* (a ? x : y) != (b ? y : x) --> (a^b) ? FALSE : TRUE */ -/* (a ? x : y) == (b ? y : x) --> (a^b) ? TRUE : FALSE */ +/* (a ? x : y) != (b ? x : y) --> (a^b & (x != y)) ? TRUE : FALSE */ +/* (a ? x : y) == (b ? x : y) --> (a^b & (x != y)) ? FALSE : TRUE */ +/* (a ? x : y) != (b ? y : x) --> (a^b | (x == y)) ? FALSE : TRUE */ +/* (a ? x : y) == (b ? y : x) --> (a^b | (x == y)) ? TRUE : FALSE */ +/* These are only valid if x and y don't have NaNs. */ (for cnd (cond vec_cond) (for eqne (eq ne) (simplify (eqne:c (cnd @0 @1 @2) (cnd @3 @1 @2)) - (if (types_match (TREE_TYPE (@0), TREE_TYPE (@3))) - (cnd (bit_xor @0 @3) { constant_boolean_node (eqne == NE_EXPR, type); } + (if (!HONOR_NANS (@1) + && types_match (TREE_TYPE (@0), TREE_TYPE (@3)) + && types_match (type, TREE_TYPE (@0))) + (cnd (bit_and (bit_xor @0 @3) (ne:type @1 @2)) + { constant_boolean_node (eqne == NE_EXPR, type); } { constant_boolean_node (eqne != NE_EXPR, type); }))) (simplify (eqne:c (cnd @0 @1 @2) (cnd @3 @2 @1)) - (if (types_match (TREE_TYPE (@0), TREE_TYPE (@3))) - (cnd (bit_xor @0 @3) { constant_boolean_node (eqne != NE_EXPR, type); } + (if (!HONOR_NANS (@1) + && types_match (TREE_TYPE (@0), TREE_TYPE (@3)) + && types_match (type, TREE_TYPE (@0))) + (cnd (bit_ior (bit_xor @0 @3) (eq:type @1 @2)) + { constant_boolean_node (eqne != NE_EXPR, type); } { constant_boolean_node (eqne == NE_EXPR, type); }))))) /* Canonicalize mask ? { 0, ... } : { -1, ...} to ~mask if the mask diff --git a/gcc/testsuite/g++.dg/torture/pr116120-1.C b/gcc/testsuite/g++.dg/torture/pr116120-1.C new file mode 100644 index 000000000000..209946f17a43 --- /dev/null +++ b/gcc/testsuite/g++.dg/torture/pr116120-1.C @@ -0,0 +1,32 @@ +// { dg-do run } +// PR tree-optimization/116120 + +// The optimization for `(a ? x : y) != (b ? x : y)` +// missed that x and y could be the same value. + +typedef int v4si __attribute((__vector_size__(1 * sizeof(int)))); +v4si f1(v4si a, v4si b, v4si c, v4si d, v4si e, v4si f) { + v4si X = a == b ? e : f; + v4si Y = c == d ? e : f; + return (X != Y); // ~(X == Y ? -1 : 0) (x ^ Y) +} + +int f2(int a, int b, int c, int d, int e, int f) { + int X = a == b ? e : f; + int Y = c == d ? e : f; + return (X != Y) ? -1 : 0; // ~(X == Y ? -1 : 0) (x ^ Y) +} + +int main() +{ + v4si a = {0}; + v4si b = {0}; // a == b, true + v4si c = {2}; + v4si d = {3}; // c == b, false + v4si e = {0}; + v4si f = e; + v4si r = f1(a,b,c,d,e, f); + int r1 = f2(a[0], b[0], c[0], d[0], e[0], f[0]); + if (r[0] != r1) + __builtin_abort(); +} diff --git a/gcc/testsuite/g++.dg/torture/pr116120-2.C b/gcc/testsuite/g++.dg/torture/pr116120-2.C new file mode 100644 index 000000000000..e9fee17a2620 --- /dev/null +++ b/gcc/testsuite/g++.dg/torture/pr116120-2.C @@ -0,0 +1,53 @@ +// { dg-do run } +// PR tree-optimization/116120 + +// The optimization for `(a ? x : y) == (b ? x : y)` +// missed that x and y could be the same value +// This can't be done if x and y support NaNs since `NaN == NaN` is always false +// And dominates the whole expression rather than supporting it. + +typedef int v1si __attribute((__vector_size__(1 * sizeof(int)))); +typedef float v1sf __attribute((__vector_size__(1 * sizeof(float)))); + +v1si f1(v1si a, v1si b, v1si c, v1si d, v1sf e, v1sf f) __attribute__((noinline)); +v1si f1(v1si a, v1si b, v1si c, v1si d, v1sf e, v1sf f) { + v1sf X = a == b ? e : f; + v1sf Y = c == d ? f : e; + return (X == Y); // ~(X == Y ? -1 : 0) (x ^ Y) +} + +int f2(int a, int b, int c, int d, float e, float f) __attribute__((noinline)); +int f2(int a, int b, int c, int d, float e, float f) { + float X = a == b ? e : f; + float Y = c == d ? f : e; + return (X == Y) ? -1 : 0; // ~(X == Y ? -1 : 0) (x ^ Y) +} + +int main() +{ + v1si a = {0}; + v1si b = {0}; // a == b, true + v1si c = {2}; + v1si d = {3}; // c == b, false + v1sf e; + v1sf f; + + /* Test signed 0s. */ + e = (v1sf){0.0}; + f = -e; + v1si r = f1(a,b,c,d,e, f); + int r1 = f2(a[0], b[0], c[0], d[0], e[0], f[0]); + if (r[0] != r1) + __builtin_abort(); + + /* Test NaNs */ +#if __FLT_HAS_QUIET_NAN__ + e = (v1sf){__builtin_nanf("")}; + f = e; + /* Test NaNs */ + r = f1(a,b,c,d,e, f); + r1 = f2(a[0], b[0], c[0], d[0], e[0], f[0]); + if (r[0] != r1) + __builtin_abort(); +#endif +} diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr111150.C b/gcc/testsuite/g++.dg/tree-ssa/pr111150.C index ac5d3ef15d83..82af8f968789 100644 --- a/gcc/testsuite/g++.dg/tree-ssa/pr111150.C +++ b/gcc/testsuite/g++.dg/tree-ssa/pr111150.C @@ -32,3 +32,13 @@ v4si f4_(v4si a, v4si b, v4si c, v4si d, v4si e, v4si f) { /* For each testcase, should produce only one VEC_COND_EXPR for X^Y. */ /* { dg-final { scan-tree-dump-times " VEC_COND_EXPR " 4 "forwprop1" } } */ +/* 2 IOR, one each for f1 and f2. + 2 AND, one each for f3 and f4. */ +/* { dg-final { scan-tree-dump-times " & " 2 "forwprop1" } } */ +/* { dg-final { scan-tree-dump-times " \\| " 2 "forwprop1" } } */ +/* { dg-final { scan-tree-dump-times " \\^ " 4 "forwprop1" } } */ +/* 8 eq comparisons from each of `a == b`/`c == d`. + 2 more to check that `e == f` + 2 ne comparisons to check that `e != f`. */ +/* { dg-final { scan-tree-dump-times " == " 10 "forwprop1" } } */ +/* { dg-final { scan-tree-dump-times " != " 2 "forwprop1" } } */ diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr111150-1.c b/gcc/testsuite/gcc.dg/tree-ssa/pr111150-1.c index 6f4b21ac6bcb..1970f7fe496f 100644 --- a/gcc/testsuite/gcc.dg/tree-ssa/pr111150-1.c +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr111150-1.c @@ -69,4 +69,13 @@ _Bool f4_(int a, int b, int c, int d, int e, int f) { /* Should generate one bit_xor_expr for each testcase. */ /* { dg-final { scan-tree-dump-not "cond_expr, " "forwprop1" } } */ +/* 2 IOR, one each for f1 and f2. + 2 AND, one each for f3 and f4. */ +/* { dg-final { scan-tree-dump-times "bit_ior_expr, " 2 "forwprop1" } } */ +/* { dg-final { scan-tree-dump-times "bit_and_expr, " 2 "forwprop1" } } */ /* { dg-final { scan-tree-dump-times "bit_xor_expr, " 4 "forwprop1" } } */ +/* 8 eq comparisons from each of `a == b`/`c == d`. + 2 more to check that `e == f` + 2 ne comparisons to check that `e != f`. */ +/* { dg-final { scan-tree-dump-times "<ne_expr, " 2 "forwprop1" } } */ +/* { dg-final { scan-tree-dump-times "<eq_expr, " 10 "forwprop1" } } */ diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr111150.c b/gcc/testsuite/gcc.dg/tree-ssa/pr111150.c index 568ae9e44b3d..6370be8cfd25 100644 --- a/gcc/testsuite/gcc.dg/tree-ssa/pr111150.c +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr111150.c @@ -20,3 +20,4 @@ v4si f2_(v4si a, v4si b, v4si c, v4si d) { /* For each testcase, should produce only one VEC_COND_EXPR for X^Y. */ /* { dg-final { scan-tree-dump-times " VEC_COND_EXPR " 2 "forwprop1" } } */ +/* { dg-final { scan-tree-dump-times " == " 4 "forwprop1" } } */