From 3a990a1263560ef28707bc623e875e75ae42041c Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 16 Jun 2020 15:28:37 -0400 Subject: Lobotomize test for float -Inf ^ -2, at least for now. Per POSIX this case should produce +0, but buildfarm member fossa (with icc (ICC) 19.0.5.281 20190815) is reporting -0. icc has a boatload of unsafe floating-point optimizations, with a corresponding boatload of not-too-well-documented compiler switches, and it seems our default use of "-mp1" isn't whacking it hard enough to keep it from misoptimizing the stanza in dpow() that checks whether y is odd. There's nothing wrong with that code (seeing that no other buildfarm member has trouble with it), so I'm content to blame this on the compiler. But without access to the compiler I'm not going to guess at what switches might be needed to fix it. For now, tweak the test case so it will accept either -0 or +0 as a correct answer. Discussion: https://postgr.es/m/E1jkyFX-0005RR-1Q@gemulon.postgresql.org --- src/test/regress/expected/float8.out | 10 ++++++---- src/test/regress/sql/float8.sql | 4 +++- 2 files changed, 9 insertions(+), 5 deletions(-) (limited to 'src') diff --git a/src/test/regress/expected/float8.out b/src/test/regress/expected/float8.out index 12b3d6223c6..c635dd7dcb6 100644 --- a/src/test/regress/expected/float8.out +++ b/src/test/regress/expected/float8.out @@ -501,10 +501,12 @@ SELECT power(float8 'inf', float8 '-inf'); 0 (1 row) -SELECT power(float8 '-inf', float8 '-2'); - power -------- - 0 +-- Intel's icc misoptimizes the code that controls the sign of this result, +-- even with -mp1. Pending a fix for that, only test for "is it zero". +SELECT power(float8 '-inf', float8 '-2') = '0'; + ?column? +---------- + t (1 row) SELECT power(float8 '-inf', float8 '-3'); diff --git a/src/test/regress/sql/float8.sql b/src/test/regress/sql/float8.sql index b628cb77b8c..288969aed65 100644 --- a/src/test/regress/sql/float8.sql +++ b/src/test/regress/sql/float8.sql @@ -140,7 +140,9 @@ SELECT power(float8 'inf', float8 '-2'); SELECT power(float8 'inf', float8 '2'); SELECT power(float8 'inf', float8 'inf'); SELECT power(float8 'inf', float8 '-inf'); -SELECT power(float8 '-inf', float8 '-2'); +-- Intel's icc misoptimizes the code that controls the sign of this result, +-- even with -mp1. Pending a fix for that, only test for "is it zero". +SELECT power(float8 '-inf', float8 '-2') = '0'; SELECT power(float8 '-inf', float8 '-3'); SELECT power(float8 '-inf', float8 '2'); SELECT power(float8 '-inf', float8 '3'); -- cgit v1.2.3