[llvm] [VPlan] Support VPWidenPointerInductionRecipes with EVL tail folding (PR #152110)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lld-x86_64-ubuntu-fast` running on `as-builder-4` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/33/builds/21721

<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/LoopVectorize/RISCV/evl-compatible-loops.ll' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
/home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/build/bin/opt -passes=loop-vectorize  -prefer-predicate-over-epilogue=predicate-else-scalar-epilogue  -mtriple=riscv64 -mattr=+v -S < /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/llvm-project/llvm/test/Transforms/LoopVectorize/RISCV/evl-compatible-loops.ll | /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/build/bin/FileCheck /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/llvm-project/llvm/test/Transforms/LoopVectorize/RISCV/evl-compatible-loops.ll # RUN: at line 2
+ /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/build/bin/opt -passes=loop-vectorize -prefer-predicate-over-epilogue=predicate-else-scalar-epilogue -mtriple=riscv64 -mattr=+v -S
+ /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/build/bin/FileCheck /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/llvm-project/llvm/test/Transforms/LoopVectorize/RISCV/evl-compatible-loops.ll
/home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/llvm-project/llvm/test/Transforms/LoopVectorize/RISCV/evl-compatible-loops.ll:113:15: error: CHECK-NEXT: expected string not found in input
; CHECK-NEXT: [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], [[FOR_BODY]] ]
              ^
<stdin>:103:10: note: scanning from here
for.body: ; preds = %scalar.ph, %for.body
         ^
<stdin>:103:10: note: with "BC_RESUME_VAL" equal to "%bc.resume.val"
for.body: ; preds = %scalar.ph, %for.body
         ^
<stdin>:103:10: note: with "SCALAR_PH" equal to "%scalar.ph"
for.body: ; preds = %scalar.ph, %for.body
         ^
<stdin>:103:10: note: with "FOR_BODY" equal to "%for.body"
for.body: ; preds = %scalar.ph, %for.body
         ^
<stdin>:104:2: note: possible intended match here
 %iv = phi i64 [ 0, %scalar.ph ], [ %iv.next, %for.body ]
 ^

Input file: <stdin>
Check file: /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/llvm-project/llvm/test/Transforms/LoopVectorize/RISCV/evl-compatible-loops.ll

-dump-input=help explains the following input dump.

Input was:
<<<<<<
            .
            .
            .
           98: scalar.ph: ; preds = %entry 
           99:  %bc.resume.val = phi i64 [ 0, %entry ] 
          100:  %bc.resume.val1 = phi ptr [ %b, %entry ] 
          101:  br label %for.body 
          102:  
          103: for.body: ; preds = %scalar.ph, %for.body 
next:113'0              X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
next:113'1                                                with "BC_RESUME_VAL" equal to "%bc.resume.val"
next:113'2                                                with "SCALAR_PH" equal to "%scalar.ph"
next:113'3                                                with "FOR_BODY" equal to "%for.body"
          104:  %iv = phi i64 [ 0, %scalar.ph ], [ %iv.next, %for.body ] 
next:113'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
next:113'4      ?                                                         possible intended match
...

```

</details>

https://github.com/llvm/llvm-project/pull/152110