https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113268
Bug ID: 113268
Summary: (i + (i + 1) * CST) AND (i + i * CST + 1 * CST) not
folded the same way
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: denis.campredon at gmail dot com
Target Milestone: ---
The two following functions should produce the same assembly with optimizations
enabled.
This lead, for exemple, to missed optimization with -Oz
---------------
#define CST 36
int foo(int i)
{
return i + (i + 1) * CST;
}
int bar(int i)
{
return i + i * CST + 1 * CST;
}
---------------
foo:
lea eax, [rdi+1]
imul eax, eax, 36
add eax, edi
ret
bar:
imul eax, edi, 37
add eax, 36
ret
