[llvm] [CostModel][X86] getShuffleCost - use processShuffleMasks to split SK_PermuteTwoSrc shuffles to legal types (PR #120599)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-ppc64-aix` running on `aix-ppc64` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/64/builds/1772

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: Transforms/PhaseOrdering/X86/hadd.ll' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 2: /home/powerllvm/powerllvm_env/aix-ppc64/clang-ppc64-aix/build/bin/opt < /home/powerllvm/powerllvm_env/aix-ppc64/clang-ppc64-aix/llvm-project/llvm/test/Transforms/PhaseOrdering/X86/hadd.ll -O3 -S -mtriple=x86_64-- -mcpu=x86-64    | /home/powerllvm/powerllvm_env/aix-ppc64/clang-ppc64-aix/build/bin/FileCheck /home/powerllvm/powerllvm_env/aix-ppc64/clang-ppc64-aix/llvm-project/llvm/test/Transforms/PhaseOrdering/X86/hadd.ll --check-prefixes=CHECK,SSE,SSE2
+ /home/powerllvm/powerllvm_env/aix-ppc64/clang-ppc64-aix/build/bin/opt -O3 -S -mtriple=x86_64-- -mcpu=x86-64
+ /home/powerllvm/powerllvm_env/aix-ppc64/clang-ppc64-aix/build/bin/FileCheck /home/powerllvm/powerllvm_env/aix-ppc64/clang-ppc64-aix/llvm-project/llvm/test/Transforms/PhaseOrdering/X86/hadd.ll --check-prefixes=CHECK,SSE,SSE2
/home/powerllvm/powerllvm_env/aix-ppc64/clang-ppc64-aix/llvm-project/llvm/test/Transforms/PhaseOrdering/X86/hadd.ll:450:14: error: SSE2-NEXT: is not on the line after the previous match
; SSE2-NEXT: [[TMP2:%.*]] = shufflevector <8 x i32> [[A]], <8 x i32> [[B:%.*]], <8 x i32> <i32 0, i32 2, i32 8, i32 10, i32 poison, i32 poison, i32 poison, i32 poison>
             ^
<stdin>:122:2: note: 'next' match was here
 %5 = shufflevector <8 x i32> %a, <8 x i32> %b, <8 x i32> <i32 0, i32 2, i32 8, i32 10, i32 poison, i32 poison, i32 poison, i32 poison>
 ^
<stdin>:118:31: note: previous match ended here
 %1 = add <8 x i32> %a, %shift
                              ^
<stdin>:119:1: note: non-matching line after previous match is here
 %2 = shufflevector <8 x i32> %b, <8 x i32> poison, <2 x i32> <i32 5, i32 6>
^
/home/powerllvm/powerllvm_env/aix-ppc64/clang-ppc64-aix/llvm-project/llvm/test/Transforms/PhaseOrdering/X86/hadd.ll:844:13: error: SSE-NEXT: is not on the line after the previous match
; SSE-NEXT: [[TMP1:%.*]] = shufflevector <8 x float> [[A]], <8 x float> [[B:%.*]], <8 x i32> <i32 0, i32 2, i32 8, i32 poison, i32 4, i32 poison, i32 poison, i32 poison>
            ^
<stdin>:219:2: note: 'next' match was here
 %4 = shufflevector <8 x float> %a, <8 x float> %b, <8 x i32> <i32 0, i32 2, i32 8, i32 poison, i32 4, i32 poison, i32 poison, i32 poison>
 ^
<stdin>:215:28: note: previous match ended here
 %a67 = fadd float %a6, %a7
                           ^
<stdin>:216:1: note: non-matching line after previous match is here
 %1 = shufflevector <8 x float> %b, <8 x float> poison, <2 x i32> <i32 5, i32 6>
^
/home/powerllvm/powerllvm_env/aix-ppc64/clang-ppc64-aix/llvm-project/llvm/test/Transforms/PhaseOrdering/X86/hadd.ll:1058:13: error: SSE-NEXT: is not on the line after the previous match
; SSE-NEXT: [[B2:%.*]] = extractelement <4 x double> [[B:%.*]], i64 2
            ^
<stdin>:282:2: note: 'next' match was here
 %b2 = extractelement <4 x double> %b, i64 2
 ^
<stdin>:278:37: note: previous match ended here
define <4 x double> @add_v4f64_0u23(<4 x double> %a, <4 x double> %b) local_unnamed_addr #0 {
                                    ^
<stdin>:279:1: note: non-matching line after previous match is here
 %1 = shufflevector <4 x double> %a, <4 x double> poison, <2 x i32> <i32 1, i32 2>
^
/home/powerllvm/powerllvm_env/aix-ppc64/clang-ppc64-aix/llvm-project/llvm/test/Transforms/PhaseOrdering/X86/hadd.ll:1100:13: error: SSE-NEXT: is not on the line after the previous match
; SSE-NEXT: [[B23:%.*]] = fadd double [[B2]], [[B3]]
            ^
<stdin>:297:2: note: 'next' match was here
 %b23 = fadd double %b2, %b3
 ^
...

```

</details>

https://github.com/llvm/llvm-project/pull/120599