From c898991d8bcfacc825097ba389ffccc5367c2b2d Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Thu, 24 Mar 2016 01:32:52 +0000 Subject: Fix x86_64 / x86 powl inaccuracy for integer exponents (bug 19848). Bug 19848 reports cases where powl on x86 / x86_64 has error accumulation, for small integer exponents, larger than permitted by glibc's accuracy goals, at least in some rounding modes. This patch further restricts the exponent range for which the small-integer-exponent logic is used to limit the possible error accumulation. Tested for x86_64 and x86 and ulps updated accordingly. [BZ #19848] * sysdeps/i386/fpu/e_powl.S (p3): Rename to p2 and change value from 8 to 4. (__ieee754_powl): Compare integer exponent against 4 not 8. * sysdeps/x86_64/fpu/e_powl.S (p3): Rename to p2 and change value from 8 to 4. (__ieee754_powl): Compare integer exponent against 4 not 8. * math/auto-libm-test-in: Add more tests of pow. * math/auto-libm-test-out: Regenerated. * sysdeps/i386/i686/fpu/multiarch/libm-test-ulps: Update. * sysdeps/x86_64/fpu/libm-test-ulps: Likewise. --- math/auto-libm-test-in | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'math/auto-libm-test-in') diff --git a/math/auto-libm-test-in b/math/auto-libm-test-in index 4b753de..34a6323 100644 --- a/math/auto-libm-test-in +++ b/math/auto-libm-test-in @@ -3717,6 +3717,44 @@ pow 0x2.000582p0 -1022 pow 2 -0x3.fe513p+8 pow 2 -0x3.fe4e8p+8 +pow 10 -1 +pow 10 -2 +pow 10 -3 +pow 10 -4 +pow 10 -5 +pow 10 -6 +pow 10 -7 + +pow 0x0.ffffffffffffffffp0 1 +pow 0x0.ffffffffffffffffp0 2 +pow 0x0.ffffffffffffffffp0 3 +pow 0x0.ffffffffffffffffp0 4 +pow 0x0.ffffffffffffffffp0 5 +pow 0x0.ffffffffffffffffp0 6 +pow 0x0.ffffffffffffffffp0 7 +pow 0x0.ffffffffffffffffp0 -1 +pow 0x0.ffffffffffffffffp0 -2 +pow 0x0.ffffffffffffffffp0 -3 +pow 0x0.ffffffffffffffffp0 -4 +pow 0x0.ffffffffffffffffp0 -5 +pow 0x0.ffffffffffffffffp0 -6 +pow 0x0.ffffffffffffffffp0 -7 + +pow 0x1.0000000000000002p0 1 +pow 0x1.0000000000000002p0 2 +pow 0x1.0000000000000002p0 3 +pow 0x1.0000000000000002p0 4 +pow 0x1.0000000000000002p0 5 +pow 0x1.0000000000000002p0 6 +pow 0x1.0000000000000002p0 7 +pow 0x1.0000000000000002p0 -1 +pow 0x1.0000000000000002p0 -2 +pow 0x1.0000000000000002p0 -3 +pow 0x1.0000000000000002p0 -4 +pow 0x1.0000000000000002p0 -5 +pow 0x1.0000000000000002p0 -6 +pow 0x1.0000000000000002p0 -7 + pow 1.0625 1.125 pow 1.5 1.03125 pow 0x1.7d1a0a6f2p+681 1.5 -- cgit v1.1