[llvm] [VPlan] Set ZeroIsPoison=false for FirstActiveLane (PR #169298)

[via llvm-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Linux-->
# :penguin: Linux x64 Test Results

* 166274 tests passed
* 2862 tests skipped
* 1 test failed

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

### LLVM
<details>
<summary>LLVM.Transforms/PhaseOrdering/AArch64/std-find.ll</summary>

```
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
/home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/opt -O3 -S /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/AArch64/std-find.ll | /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/FileCheck /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/AArch64/std-find.ll
# executed command: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/opt -O3 -S /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/AArch64/std-find.ll
# note: command had no output on stdout or stderr
# executed command: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/FileCheck /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/AArch64/std-find.ll
# .---command stderr------------
# | /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/AArch64/std-find.ll:31:15: error: CHECK-NEXT: expected string not found in input
# | ; CHECK-NEXT: [[TMP5:%.*]] = tail call i64 @llvm.experimental.cttz.elts.i64.v8i1(<8 x i1> [[TMP0]], i1 true)
# |               ^
# | <stdin>:32:19: note: scanning from here
# | vector.early.exit: ; preds = %middle.split
# |                   ^
# | <stdin>:32:19: note: with "TMP0" equal to "%0"
# | vector.early.exit: ; preds = %middle.split
# |                   ^
# | <stdin>:33:2: note: possible intended match here
# |  %5 = tail call i64 @llvm.experimental.cttz.elts.i64.v8i1(<8 x i1> %0, i1 false)
# |  ^
# | /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/AArch64/std-find.ll:176:15: error: CHECK-NEXT: expected string not found in input
# | ; CHECK-NEXT: [[TMP11:%.*]] = tail call i64 @llvm.experimental.cttz.elts.i64.v8i1(<8 x i1> [[TMP4]], i1 true)
# |               ^
# | <stdin>:119:19: note: scanning from here
# | vector.early.exit: ; preds = %middle.split
# |                   ^
# | <stdin>:119:19: note: with "TMP4" equal to "%6"
# | vector.early.exit: ; preds = %middle.split
# |                   ^
# | <stdin>:120:2: note: possible intended match here
# |  %11 = tail call i64 @llvm.experimental.cttz.elts.i64.v8i1(<8 x i1> %6, i1 false)
# |  ^
# | 
# | Input file: <stdin>
# | Check file: /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/AArch64/std-find.ll
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             .
# |             .
# |             .
# |            27:  br i1 %4, label %middle.split, label %vector.body, !llvm.loop !0 
# |            28:  
# |            29: middle.split: ; preds = %vector.body 
# |            30:  br i1 %2, label %vector.early.exit, label %return 
# |            31:  
# |            32: vector.early.exit: ; preds = %middle.split 
# | next:31'0                        X~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
# | next:31'1                                                  with "TMP0" equal to "%0"
# |            33:  %5 = tail call i64 @llvm.experimental.cttz.elts.i64.v8i1(<8 x i1> %0, i1 false) 
# | next:31'0      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# | next:31'2       ?                                                                                possible intended match
# |            34:  %6 = add i64 %index, %5 
# | next:31'0      ~~~~~~~~~~~~~~~~~~~~~~~~~
# |            35:  %7 = shl i64 %6, 1 
# | next:31'0      ~~~~~~~~~~~~~~~~~~~~
# |            36:  %8 = getelementptr i8, ptr %first.coerce, i64 %7 
# | next:31'0      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |            37:  br label %return 
# | next:31'0      ~~~~~~~~~~~~~~~~~~
# |            38:  
# | next:31'0      ~
# |             .
# |             .
# |             .
# |           114:  
# |           115: loop.header.i.preheader2: ; preds = %loop.header.i.preheader, %middle.block 
# |           116:  %ptr.iv.i.ph = phi ptr [ %first, %loop.header.i.preheader ], [ %5, %middle.block ] 
# |           117:  br label %loop.header.i 
# |           118:  
# |           119: vector.early.exit: ; preds = %middle.split 
# | next:176'0                       X~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
# | next:176'1                                                 with "TMP4" equal to "%6"
# |           120:  %11 = tail call i64 @llvm.experimental.cttz.elts.i64.v8i1(<8 x i1> %6, i1 false) 
# | next:176'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# | next:176'2      ?                                                                                 possible intended match
# |           121:  %12 = add i64 %index, %11 
# | next:176'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |           122:  %13 = shl i64 %12, 1 
# | next:176'0     ~~~~~~~~~~~~~~~~~~~~~~
# |           123:  %14 = getelementptr i8, ptr %first, i64 %13 
# | next:176'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |           124:  br label %std_find_generic_impl.exit 
# | next:176'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |           125:  
# | next:176'0     ~
# |             .
# |             .
# |             .
# | >>>>>>
# `-----------------------------
# 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/169298