From 290358f770d21d9204ea621f839ee8fba606a275 Mon Sep 17 00:00:00 2001 From: Revital Eres Date: Sun, 6 May 2007 10:35:42 +0000 Subject: [PATCH] Fix PR30957 From-SVN: r124471 --- gcc/ChangeLog | 6 ++++++ gcc/loop-unroll.c | 35 +++++++++++++++++++++++++++++--- gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/gcc.dg/pr30957-1.c | 30 +++++++++++++++++++++++++++ 4 files changed, 73 insertions(+), 3 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/pr30957-1.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 17eb8e4a2f8..d703c48294d 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2007-06-05 Revital Eres + + PR 30957 + * loop-unroll.c (insert_var_expansion_initialization): + Initialize the expansions with -zero instead of +zero. + 2007-05-05 Aurelien Jarno * config/pa/pa.md: Split tgd_load, tld_load and tie_load diff --git a/gcc/loop-unroll.c b/gcc/loop-unroll.c index d1322d11e39..c5653b2c051 100644 --- a/gcc/loop-unroll.c +++ b/gcc/loop-unroll.c @@ -2014,7 +2014,30 @@ expand_var_during_unrolling (struct var_to_expand *ve, rtx insn) /* Initialize the variable expansions in loop preheader. Callbacks for htab_traverse. PLACE_P is the loop-preheader basic block where the initialization of the expansions - should take place. */ + should take place. The expansions are initialized with (-0) + when the operation is plus or minus to honor sign zero. + This way we can prevent cases where the sign of the final result is + effected by the sign of the expansion. + Here is an example to demonstrate this: + + for (i = 0 ; i < n; i++) + sum += something; + + ==> + + sum += something + .... + i = i+1; + sum1 += something + .... + i = i+1 + sum2 += something; + .... + + When SUM is initialized with -zero and SOMETHING is also -zero; the + final result of sum should be -zero thus the expansions sum1 and sum2 + should be initialized with -zero as well (otherwise we will get +zero + as the final result). */ static int insert_var_expansion_initialization (void **slot, void *place_p) @@ -2023,7 +2046,9 @@ insert_var_expansion_initialization (void **slot, void *place_p) basic_block place = (basic_block)place_p; rtx seq, var, zero_init, insn; unsigned i; - + enum machine_mode mode = GET_MODE (ve->reg); + bool honor_signed_zero_p = HONOR_SIGNED_ZEROS (mode); + if (VEC_length (rtx, ve->var_expansions) == 0) return 1; @@ -2031,7 +2056,11 @@ insert_var_expansion_initialization (void **slot, void *place_p) if (ve->op == PLUS || ve->op == MINUS) for (i = 0; VEC_iterate (rtx, ve->var_expansions, i, var); i++) { - zero_init = CONST0_RTX (GET_MODE (var)); + if (honor_signed_zero_p) + zero_init = simplify_gen_unary (NEG, mode, CONST0_RTX (mode), mode); + else + zero_init = CONST0_RTX (mode); + emit_move_insn (var, zero_init); } else if (ve->op == MULT) diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 2c6bc0ab6d1..bcec964d959 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2007-06-05 Revital Eres + + PR 30957 + * gcc.dg/pr30957-1.c: New test. + 2007-05-05 Jerry DeLisle PR fortran/31251 diff --git a/gcc/testsuite/gcc.dg/pr30957-1.c b/gcc/testsuite/gcc.dg/pr30957-1.c new file mode 100644 index 00000000000..26d5de7f6f7 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr30957-1.c @@ -0,0 +1,30 @@ +/* { dg-do run { xfail vax-*-* powerpc-*-*spe } } */ +/* { dg-options "-O2 -funroll-loops -funsafe-math-optimizations -fvariable-expansion-in-unroller -dL" } */ + +extern void abort (void); +extern void exit (int); + +float +foo (float d, int n) +{ + unsigned i; + float accum = d; + + for (i = 0; i < n; i++) + accum += d; + + return accum; +} + +int +main () +{ + if (__builtin_copysignf (1.0, foo (0.0 / -5.0, 10)) != -1.0) + abort (); + exit (0); +} + +/* { dg-final { scan-rtl-dump "Expanding Accumulator" "loop2_unroll" } } */ +/* { dg-final { cleanup-rtl-dump "loop*" } } */ + +