https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69308
Bug ID: 69308
Summary: ifcombine joins together floating point expression
with side effects
Product: gcc
Version: 5.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: mtliang at synopsys dot com
Target Milestone: ---
Created attachment 37366
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37366&action=edit
test case
With floating point exceptions enabled, passing a signaling NaN into the
expression ( !isnan(x) && x > 0.0 ) ends up with the second half evaluating and
raising an FPE. Compiling with the -fsignaling-nans flag does not help, and
the only way to get past this is to disable this pass with the
-fdisable-tree-ifcombine flag.
Should ifcombine look at the -fsignaling-nans flag and disqualify floating
point expressions for that case?
The attached test case should print "pass" for all cases.
With the current GCC the optimized build fails with FPE unless built with
ifcombine disabled.
