Compiler doesn't canonicalize truncates in SCEV expresions.

[llvmbot]

Bugzilla Link	19168
Version	trunk
OS	All
Attachments	Reproducer
Reporter	LLVM Bugzilla Contributor

Extended Description

LLVM doesn't perform a canonicalization of trunc expressions, and due to that round-trip of normalization-denormalization cant yield an expression, different from the original one. Post-Inc transformation gives-up in this case.

Attached is a test case revealing the issue.

[hfinkel]

mentioned in issue llvm/llvm-bugzilla-archive#25170

[atrick]

mentioned in issue llvm/llvm-bugzilla-archive#25170