Yingwei Zheng 6d667d4b26
[InstCombine] Combine const GEP chains
This patch reverts rGae739aefd7473517d3f08b5c8d08a66c7f469198 to address performance regressions reported by our [CI](https://github.com/dtcxzyw/llvm-ci/issues/137) after rG2ec1d0f427c7822540352c0c14d057e7bfe4f77b.

For example:
```
define ptr @const_gep_chain(ptr %p, i64 %a) {
    %p1 = getelementptr inbounds i8, ptr %p, i64 %a
    %p2 = getelementptr inbounds i8, ptr %p1, i64 1
    %p3 = getelementptr inbounds i8, ptr %p2, i64 2
    %p4 = getelementptr inbounds i8, ptr %p3, i64 3
    ret ptr %p4
}
```
The last three GEPs will not be folded since rG2ec1d0f427c7822540352c0c14d057e7bfe4f77b.

I think it is appropriate to remove this code because there is no compile-time regression reported in our benchmarks.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D149240
2023-05-02 00:28:39 +08:00
..
2022-08-24 22:41:38 +00:00
2023-02-20 10:49:44 +01:00
2022-12-15 12:03:47 -05:00

This directory contains test cases for the instcombine transformation.  The
dated tests are actual bug tests, whereas the named tests are used to test
for features that the this pass should be capable of performing.