From 2b3969faee4094c5b857bf024e8ce4b7d832dc2d Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Mon, 14 Aug 2006 11:55:52 +0000 Subject: [PATCH] re PR rtl-optimization/28634 (rounding problem with -fdelayed-branch on hppa/mips) gcc/ PR rtl-optimization/28634 * reorg.c (fill_slots_from_thread): Do not assume A + X - X == A for floating-point modes unless flag_unsafe_math_optimizations. gcc/testsuite/ PR rtl-optimization/28634 * gcc.c-torture/execute/ieee/pr28634.c: New test. From-SVN: r116124 --- gcc/ChangeLog | 6 ++++++ gcc/reorg.c | 2 ++ gcc/testsuite/ChangeLog | 5 +++++ .../gcc.c-torture/execute/ieee/pr28634.c | 15 +++++++++++++++ 4 files changed, 28 insertions(+) create mode 100644 gcc/testsuite/gcc.c-torture/execute/ieee/pr28634.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 37fbac8519c..8a53adee42f 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2006-08-14 Richard Sandiford + + PR rtl-optimization/28634 + * reorg.c (fill_slots_from_thread): Do not assume A + X - X == A + for floating-point modes unless flag_unsafe_math_optimizations. + 2006-08-13 Alexandre Oliva Andrew Pinski diff --git a/gcc/reorg.c b/gcc/reorg.c index 42ecda0db4c..8c097dca412 100644 --- a/gcc/reorg.c +++ b/gcc/reorg.c @@ -2817,6 +2817,8 @@ fill_slots_from_thread (rtx insn, rtx condition, rtx thread, dest = SET_DEST (pat), src = SET_SRC (pat); if ((GET_CODE (src) == PLUS || GET_CODE (src) == MINUS) && rtx_equal_p (XEXP (src, 0), dest) + && (!FLOAT_MODE_P (GET_MODE (src)) + || flag_unsafe_math_optimizations) && ! reg_overlap_mentioned_p (dest, XEXP (src, 1)) && ! side_effects_p (pat)) { diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index de4f9e6a789..7481db0ec6d 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2006-08-14 Richard Sandiford + + PR rtl-optimization/28634 + * gcc.c-torture/execute/ieee/pr28634.c: New test. + 2006-08-13 Alexandre Oliva PR c/27184 diff --git a/gcc/testsuite/gcc.c-torture/execute/ieee/pr28634.c b/gcc/testsuite/gcc.c-torture/execute/ieee/pr28634.c new file mode 100644 index 00000000000..a0c525497d7 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/ieee/pr28634.c @@ -0,0 +1,15 @@ +/* PR rtl-optimization/28634. On targets with delayed branches, + dbr_schedule could do the next iteration's addition in the + branch delay slot, then subtract the value again if the branch + wasn't taken. This can lead to rounding errors. */ +double x = -0x1.0p53; +double y = 1; +int +main (void) +{ + while (y > 0) + y += x; + if (y != x + 1) + abort (); + exit (0); +} -- 2.30.2