Commit Graph

2 Commits

Author SHA1 Message Date
Richard Smith 0c6124ba82 PR17381: Treat undefined behavior during expression evaluation as an unmodeled
side-effect, so that we don't allow speculative evaluation of such expressions
during code generation.

This caused a diagnostic quality regression, so fix constant expression
diagnostics to prefer either the first "can't be constant folded" diagnostic or
the first "not a constant expression" diagnostic depending on the kind of
evaluation we're doing. This was always the intent, but didn't quite work
correctly before.

This results in certain initializers that used to be constant initializers to
no longer be; in particular, things like:

  float f = 1e100;

are no longer accepted in C. This seems appropriate, as such constructs would
lead to code being executed if sanitizers are enabled.

llvm-svn: 254574
2015-12-03 01:36:22 +00:00
Josh Magee 4d1a79b8c0 Catch more cases when diagnosing integer-constant-expression overflows.
When visiting AssignmentOps, keep evaluating after a failure (when possible) in
order to identify overflow in subexpressions.

Differential Revision: http://reviews.llvm.org/D1238

llvm-svn: 228202
2015-02-04 21:50:20 +00:00