From 4060283decf711ed95a6c4993ffeaba39f8cd40a Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Tue, 24 Jun 2014 21:00:08 +0000 Subject: Fix x86/x86_64 expm1l spurious underflow exceptions (bug 16539). This patch fixes bug 16539, spurious underflow exceptions from x86 / x86-64 expm1l. The problem is that the computation of a base-2 exponent with extra precision involves spurious underflows for arguments that are small but not subnormal, so a check is added to just return the argument in those cases. (If the argument *is* subnormal, underflowing is correct and the existing code will always underflow, so it suffices to keep using the existing code in that case; some expm1 implementations have a bug (bug 16353) with missing underflow exceptions, but I don't think there's such a bug in this particular version.) Tested x86_64 and x86; no ulps updates needed. (auto-libm-test-out diffs omitted below.) [BZ #16539] * sysdeps/i386/fpu/e_expl.S (IEEE754_EXPL) [USE_AS_EXPM1L]: Just return the argument for normal arguments with exponent below -64. * sysdeps/x86_64/fpu/e_expl.S (IEEE754_EXPL) [USE_AS_EXPM1L]: Likewise. * math/auto-libm-test-in: Add another test of expm1. * math/auto-libm-test-out: Regenerated. --- math/auto-libm-test-out | 81 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 81 insertions(+) (limited to 'math/auto-libm-test-out') diff --git a/math/auto-libm-test-out b/math/auto-libm-test-out index d1ec2be279..ced5283ab2 100644 --- a/math/auto-libm-test-out +++ b/math/auto-libm-test-out @@ -93045,6 +93045,87 @@ expm1 -0x1p-100 = expm1 tonearest ldbl-128ibm -0x1p-100L : -0xf.ffffffffffffffffffffffff8p-104L : inexact-ok = expm1 towardzero ldbl-128ibm -0x1p-100L : -0xf.ffffffffffffffffffffffff8p-104L : inexact-ok = expm1 upward ldbl-128ibm -0x1p-100L : -0xf.ffffffffffffffffffffffff8p-104L : inexact-ok +expm1 0x4.0000000000000028p-16384 missing-underflow += expm1 downward flt-32 0x8p-152f : 0x8p-152f : inexact-ok underflow underflow-ok errno-erange-ok += expm1 tonearest flt-32 0x8p-152f : 0x8p-152f : inexact-ok underflow underflow-ok errno-erange-ok += expm1 towardzero flt-32 0x8p-152f : 0x8p-152f : inexact-ok underflow underflow-ok errno-erange-ok += expm1 upward flt-32 0x8p-152f : 0x1p-148f : inexact-ok underflow underflow-ok errno-erange-ok += expm1 downward dbl-64 0x8p-152 : 0x8p-152 : inexact-ok += expm1 tonearest dbl-64 0x8p-152 : 0x8p-152 : inexact-ok += expm1 towardzero dbl-64 0x8p-152 : 0x8p-152 : inexact-ok += expm1 upward dbl-64 0x8p-152 : 0x8.0000000000008p-152 : inexact-ok += expm1 downward ldbl-96-intel 0x8p-152L : 0x8p-152L : inexact-ok += expm1 tonearest ldbl-96-intel 0x8p-152L : 0x8p-152L : inexact-ok += expm1 towardzero ldbl-96-intel 0x8p-152L : 0x8p-152L : inexact-ok += expm1 upward ldbl-96-intel 0x8p-152L : 0x8.000000000000001p-152L : inexact-ok += expm1 downward ldbl-96-m68k 0x8p-152L : 0x8p-152L : inexact-ok += expm1 tonearest ldbl-96-m68k 0x8p-152L : 0x8p-152L : inexact-ok += expm1 towardzero ldbl-96-m68k 0x8p-152L : 0x8p-152L : inexact-ok += expm1 upward ldbl-96-m68k 0x8p-152L : 0x8.000000000000001p-152L : inexact-ok += expm1 downward ldbl-128 0x8p-152L : 0x8p-152L : inexact-ok += expm1 tonearest ldbl-128 0x8p-152L : 0x8p-152L : inexact-ok += expm1 towardzero ldbl-128 0x8p-152L : 0x8p-152L : inexact-ok += expm1 upward ldbl-128 0x8p-152L : 0x8.0000000000000000000000000008p-152L : inexact-ok += expm1 downward ldbl-128ibm 0x8p-152L : 0x8p-152L : inexact-ok += expm1 tonearest ldbl-128ibm 0x8p-152L : 0x8p-152L : inexact-ok += expm1 towardzero ldbl-128ibm 0x8p-152L : 0x8p-152L : inexact-ok += expm1 upward ldbl-128ibm 0x8p-152L : 0x8.00000000000000000000000004p-152L : inexact-ok += expm1 downward flt-32 0x0p+0f : 0x0p+0f : inexact-ok += expm1 tonearest flt-32 0x0p+0f : 0x0p+0f : inexact-ok += expm1 towardzero flt-32 0x0p+0f : 0x0p+0f : inexact-ok += expm1 upward flt-32 0x0p+0f : 0x0p+0f : inexact-ok += expm1 downward dbl-64 0x0p+0 : 0x0p+0 : inexact-ok += expm1 tonearest dbl-64 0x0p+0 : 0x0p+0 : inexact-ok += expm1 towardzero dbl-64 0x0p+0 : 0x0p+0 : inexact-ok += expm1 upward dbl-64 0x0p+0 : 0x0p+0 : inexact-ok += expm1 downward ldbl-96-intel 0x0p+0L : 0x0p+0L : inexact-ok += expm1 tonearest ldbl-96-intel 0x0p+0L : 0x0p+0L : inexact-ok += expm1 towardzero ldbl-96-intel 0x0p+0L : 0x0p+0L : inexact-ok += expm1 upward ldbl-96-intel 0x0p+0L : 0x0p+0L : inexact-ok += expm1 downward ldbl-96-m68k 0x0p+0L : 0x0p+0L : inexact-ok += expm1 tonearest ldbl-96-m68k 0x0p+0L : 0x0p+0L : inexact-ok += expm1 towardzero ldbl-96-m68k 0x0p+0L : 0x0p+0L : inexact-ok += expm1 upward ldbl-96-m68k 0x0p+0L : 0x0p+0L : inexact-ok += expm1 downward ldbl-128 0x0p+0L : 0x0p+0L : inexact-ok += expm1 tonearest ldbl-128 0x0p+0L : 0x0p+0L : inexact-ok += expm1 towardzero ldbl-128 0x0p+0L : 0x0p+0L : inexact-ok += expm1 upward ldbl-128 0x0p+0L : 0x0p+0L : inexact-ok += expm1 downward ldbl-128ibm 0x0p+0L : 0x0p+0L : inexact-ok += expm1 tonearest ldbl-128ibm 0x0p+0L : 0x0p+0L : inexact-ok += expm1 towardzero ldbl-128ibm 0x0p+0L : 0x0p+0L : inexact-ok += expm1 upward ldbl-128ibm 0x0p+0L : 0x0p+0L : inexact-ok += expm1 downward dbl-64 0x4p-1076 : 0x4p-1076 : inexact-ok underflow underflow-ok errno-erange-ok += expm1 tonearest dbl-64 0x4p-1076 : 0x4p-1076 : inexact-ok underflow underflow-ok errno-erange-ok += expm1 towardzero dbl-64 0x4p-1076 : 0x4p-1076 : inexact-ok underflow underflow-ok errno-erange-ok += expm1 upward dbl-64 0x4p-1076 : 0x8p-1076 : inexact-ok underflow underflow-ok errno-erange-ok += expm1 downward ldbl-96-intel 0x4p-1076L : 0x4p-1076L : inexact-ok += expm1 tonearest ldbl-96-intel 0x4p-1076L : 0x4p-1076L : inexact-ok += expm1 towardzero ldbl-96-intel 0x4p-1076L : 0x4p-1076L : inexact-ok += expm1 upward ldbl-96-intel 0x4p-1076L : 0x4.0000000000000008p-1076L : inexact-ok += expm1 downward ldbl-96-m68k 0x4p-1076L : 0x4p-1076L : inexact-ok += expm1 tonearest ldbl-96-m68k 0x4p-1076L : 0x4p-1076L : inexact-ok += expm1 towardzero ldbl-96-m68k 0x4p-1076L : 0x4p-1076L : inexact-ok += expm1 upward ldbl-96-m68k 0x4p-1076L : 0x4.0000000000000008p-1076L : inexact-ok += expm1 downward ldbl-128 0x4p-1076L : 0x4p-1076L : inexact-ok += expm1 tonearest ldbl-128 0x4p-1076L : 0x4p-1076L : inexact-ok += expm1 towardzero ldbl-128 0x4p-1076L : 0x4p-1076L : inexact-ok += expm1 upward ldbl-128 0x4p-1076L : 0x4.0000000000000000000000000004p-1076L : inexact-ok += expm1 downward ldbl-128ibm 0x4p-1076L : 0x4p-1076L : inexact-ok underflow underflow-ok errno-erange-ok += expm1 tonearest ldbl-128ibm 0x4p-1076L : 0x4p-1076L : inexact-ok underflow underflow-ok errno-erange-ok += expm1 towardzero ldbl-128ibm 0x4p-1076L : 0x4p-1076L : inexact-ok underflow underflow-ok errno-erange-ok += expm1 upward ldbl-128ibm 0x4p-1076L : 0x8p-1076L : inexact-ok underflow underflow-ok errno-erange-ok += expm1 downward ldbl-96-intel 0x4.0000000000000028p-16384L : 0x4.0000000000000028p-16384L : inexact-ok += expm1 tonearest ldbl-96-intel 0x4.0000000000000028p-16384L : 0x4.0000000000000028p-16384L : inexact-ok += expm1 towardzero ldbl-96-intel 0x4.0000000000000028p-16384L : 0x4.0000000000000028p-16384L : inexact-ok += expm1 upward ldbl-96-intel 0x4.0000000000000028p-16384L : 0x4.000000000000003p-16384L : inexact-ok += expm1 downward ldbl-96-m68k 0x4.0000000000000028p-16384L : 0x4.0000000000000028p-16384L : inexact-ok += expm1 tonearest ldbl-96-m68k 0x4.0000000000000028p-16384L : 0x4.0000000000000028p-16384L : inexact-ok += expm1 towardzero ldbl-96-m68k 0x4.0000000000000028p-16384L : 0x4.0000000000000028p-16384L : inexact-ok += expm1 upward ldbl-96-m68k 0x4.0000000000000028p-16384L : 0x4.000000000000003p-16384L : inexact-ok += expm1 downward ldbl-128 0x4.0000000000000028p-16384L : 0x4.0000000000000028p-16384L : inexact-ok += expm1 tonearest ldbl-128 0x4.0000000000000028p-16384L : 0x4.0000000000000028p-16384L : inexact-ok += expm1 towardzero ldbl-128 0x4.0000000000000028p-16384L : 0x4.0000000000000028p-16384L : inexact-ok += expm1 upward ldbl-128 0x4.0000000000000028p-16384L : 0x4.0000000000000028000000000004p-16384L : inexact-ok fma 1.0 2.0 3.0 = fma downward flt-32 0x1p+0f 0x2p+0f 0x3p+0f : 0x5p+0f : = fma tonearest flt-32 0x1p+0f 0x2p+0f 0x3p+0f : 0x5p+0f : -- cgit 1.4.1