From 378393da613d7c182ce3370696ec47a5a5cb2aef Mon Sep 17 00:00:00 2001 From: Roger Sayle Date: Sat, 1 Jun 2002 16:56:08 +0000 Subject: tree.c (real_minus_onep): New function to test for -1.0. * tree.c (real_minus_onep): New function to test for -1.0. * fold-const.c (fold) [MULT_EXPR]: Optimize -1.0*x into -x. * gcc.dg/fnegate-1.c: New test case. From-SVN: r54149 --- gcc/ChangeLog | 5 ++ gcc/fold-const.c | 8 +++ gcc/testsuite/ChangeLog | 4 ++ gcc/testsuite/gcc.dg/fnegate-1.c | 113 +++++++++++++++++++++++++++++++++++++++ gcc/tree.c | 16 ++++++ gcc/tree.h | 1 + 6 files changed, 147 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/fnegate-1.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 0dd65f3..9a4a44b 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,10 @@ 2002-06-01 Roger Sayle + * tree.c (real_minus_onep): New function to test for -1.0. + * fold-const.c (fold) [MULT_EXPR]: Optimize -1.0*x into -x. + +2002-06-01 Roger Sayle + * fold-const.c (fold_truthop): Transform "a || b" into "(a|b) != 0" and "!p && !q" into "(p|q) == 0" under suitable conditions. diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 0998a93..947d575 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -5370,6 +5370,14 @@ fold (expr) so we can do this anyway. */ if (real_onep (arg1)) return non_lvalue (convert (type, arg0)); + + /* Transform x * -1.0 into -x. This should be safe for NaNs, + signed zeros and signed infinities, but is currently + restricted to "unsafe math optimizations" just in case. */ + if (flag_unsafe_math_optimizations + && real_minus_onep (arg1)) + return fold (build1 (NEGATE_EXPR, type, arg0)); + /* x*2 is x+x */ if (! wins && real_twop (arg1) && (*lang_hooks.decls.global_bindings_p) () == 0 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 8e06317..5f2d0b7 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2002-06-01 Roger Sayle + + * gcc.dg/fnegate-1.c: New test case. + 2002-05-30 Osku Salerma * gcc.c-torture/execute/mayalias-1.c: New file. diff --git a/gcc/testsuite/gcc.dg/fnegate-1.c b/gcc/testsuite/gcc.dg/fnegate-1.c new file mode 100644 index 0000000..ad0f4e0 --- /dev/null +++ b/gcc/testsuite/gcc.dg/fnegate-1.c @@ -0,0 +1,113 @@ +/* Copyright (C) 2002 Free Software Foundation. + + Test floating point negation produces the expected results. + + Written by Roger Sayle, 21st May 2002. */ + +/* { dg-do run } */ +/* { dg-options "-O2 -ffast-math" } */ + +extern void abort (); + + +double +dneg (double x) +{ + return -x; +} + +double +dmult (double x) +{ + return -1.0 * x; +} + +double +ddiv (double x) +{ + return x / -1.0; +} + + +float +fneg (float x) +{ + return -x; +} + +float +fmult (float x) +{ + return -1.0f * x; +} + +float +fdiv (float x) +{ + return x / -1.0f; +} + + +void +ftest(float src, float dst) +{ + if (fneg (src) != dst) + abort (); + + if (src != fneg (dst)) + abort (); + + if (fmult (src) != dst) + abort (); + + if (src != fmult (dst)) + abort (); + + if (fdiv (src) != dst) + abort (); + + if (src != fdiv(dst)) + abort (); +} + +void +dtest(double src, double dst) +{ + if (dneg (src) != dst) + abort (); + + if (src != dneg (dst)) + abort (); + + if (dmult (src) != dst) + abort (); + + if (src != dmult (dst)) + abort (); + + if (ddiv (src) != dst) + abort (); + + if (src != ddiv(dst)) + abort (); +} + + +int +main () +{ + ftest (1.0f, -1.0f); + ftest (2.0f, -2.0f); + ftest (-3.0f, 3.0f); + ftest (0.0f, -0.0f); + ftest (-0.0f, 0.0f); + + dtest (1.0, -1.0); + dtest (2.0, -2.0); + dtest (-3.0, 3.0); + dtest (0.0, -0.0); + dtest (-0.0, 0.0); + + return 0; +} + diff --git a/gcc/tree.c b/gcc/tree.c index 15f156a..04ae6ce 100644 --- a/gcc/tree.c +++ b/gcc/tree.c @@ -892,6 +892,22 @@ real_twop (expr) && real_zerop (TREE_IMAGPART (expr)))); } +/* Return 1 if EXPR is the real constant minus one. */ + +int +real_minus_onep (expr) + tree expr; +{ + STRIP_NOPS (expr); + + return ((TREE_CODE (expr) == REAL_CST + && ! TREE_CONSTANT_OVERFLOW (expr) + && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconstm1)) + || (TREE_CODE (expr) == COMPLEX_CST + && real_minus_onep (TREE_REALPART (expr)) + && real_zerop (TREE_IMAGPART (expr)))); +} + /* Nonzero if EXP is a constant or a cast of a constant. */ int diff --git a/gcc/tree.h b/gcc/tree.h index fffad7a..34385da 100644 --- a/gcc/tree.h +++ b/gcc/tree.h @@ -2850,6 +2850,7 @@ extern void expand_pending_sizes PARAMS ((tree)); extern int real_onep PARAMS ((tree)); extern int real_twop PARAMS ((tree)); +extern int real_minus_onep PARAMS ((tree)); extern void gcc_obstack_init PARAMS ((struct obstack *)); extern void init_obstacks PARAMS ((void)); extern void build_common_tree_nodes PARAMS ((int)); -- cgit v1.1