[llvm] [AMDGPU] Fix LSR cost comparator that regressed GFX9+ occupancy (PR #204344)

[via llvm-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Windows-->
# :window: Windows x64 Test Results

* 136353 tests passed
* 3510 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### LLVM
<details>
<summary>LLVM.Transforms/LoopStrengthReduce/AMDGPU/lsr-icmpzero-mixed-ptr-width.ll</summary>

```
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
c:\_work\llvm-project\llvm-project\build\bin\opt.exe -passes=loop-reduce -S -mcpu=gfx942 C:\_work\llvm-project\llvm-project\llvm\test\Transforms\LoopStrengthReduce\AMDGPU\lsr-icmpzero-mixed-ptr-width.ll | c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe C:\_work\llvm-project\llvm-project\llvm\test\Transforms\LoopStrengthReduce\AMDGPU\lsr-icmpzero-mixed-ptr-width.ll
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\opt.exe' -passes=loop-reduce -S -mcpu=gfx942 'C:\_work\llvm-project\llvm-project\llvm\test\Transforms\LoopStrengthReduce\AMDGPU\lsr-icmpzero-mixed-ptr-width.ll'
# note: command had no output on stdout or stderr
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe' 'C:\_work\llvm-project\llvm-project\llvm\test\Transforms\LoopStrengthReduce\AMDGPU\lsr-icmpzero-mixed-ptr-width.ll'
# .---command stderr------------
# | C:\_work\llvm-project\llvm-project\llvm\test\Transforms\LoopStrengthReduce\AMDGPU\lsr-icmpzero-mixed-ptr-width.ll:16:15: error: CHECK-NEXT: expected string not found in input
# | ; CHECK-NEXT: [[LSR_IV:%.*]] = phi i64 [ [[LSR_IV_NEXT:%.*]], %[[LOOP]] ], [ 0, %[[ENTRY]] ]
# |               ^
# | <stdin>:10:6: note: scanning from here
# | loop: ; preds = %loop, %entry
# |      ^
# | <stdin>:10:6: note: with "LOOP" equal to "loop"
# | loop: ; preds = %loop, %entry
# |      ^
# | <stdin>:10:6: note: with "ENTRY" equal to "entry"
# | loop: ; preds = %loop, %entry
# |      ^
# | <stdin>:11:2: note: possible intended match here
# |  %src = phi ptr [ null, %entry ], [ %src.next, %loop ]
# |  ^
# | 
# | Input file: <stdin>
# | Check file: C:\_work\llvm-project\llvm-project\llvm\test\Transforms\LoopStrengthReduce\AMDGPU\lsr-icmpzero-mixed-ptr-width.ll
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |            .
# |            .
# |            .
# |            5:  
# |            6: define amdgpu_kernel void @icmpzero_mixed_ptr_width(ptr addrspace(5) %scratch) #0 { 
# |            7: entry: 
# |            8:  br label %loop 
# |            9:  
# |           10: loop: ; preds = %loop, %entry 
# | next:16'0         {                           search range start (exclusive)
# | next:16'1                                     error: no match found in search range
# | next:16'2                                     with "LOOP" equal to "loop"
# | next:16'3                                     with "ENTRY" equal to "entry"
# |           11:  %src = phi ptr [ null, %entry ], [ %src.next, %loop ] 
# | next:16'4      ?                                                       possible intended match
# |           12:  %dst = phi ptr addrspace(5) [ %scratch, %entry ], [ %dst.next, %loop ] 
# |           13:  %d0 = load double, ptr addrspace(5) %dst, align 8 
# |           14:  %s0 = load double, ptr %src, align 8 
# |           15:  %dst.1 = getelementptr i8, ptr addrspace(5) %dst, i32 8 
# |           16:  %d1 = load double, ptr addrspace(5) %dst.1, align 8 
# |            .
# |            .
# |            .
# |           27:  
# |           28: exit: ; preds = %loop 
# |           29:  ret void 
# |           30: } 
# |           31:  
# |           32: attributes #0 = { "target-cpu"="gfx942" } 
# | next:16'5                                               } search range end (exclusive)
# | >>>>>>
# `-----------------------------
# error: command failed with exit status: 1

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/204344