[ValueTracking] Improve impliesPoison to look into overflow intrinsics

This update supports the following transformation:

```
select(extract(mul_with_overflow(a, _), _), (a == 0), false)
=>
and(extract(mul_with_overflow(a, _), _), (a == 0))
```

which is correct because if `a` was poison the select's condition was
also poison.

This update is splitted from D101423.

1 files changed, 2 insertions, 1 deletions

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 369ac42..e5b0345 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -5020,7 +5020,8 @@ static bool directlyImpliesPoison(const Value *ValAssumedPoison,
     // V0's elements are all poison or not. (e.g., add_with_overflow)
     const WithOverflowInst *II;
     if (match(I, m_ExtractValue(m_WithOverflowInst(II))) &&
-        match(ValAssumedPoison, m_ExtractValue(m_Specific(II))))
+        (match(ValAssumedPoison, m_ExtractValue(m_Specific(II))) ||
+         llvm::is_contained(II->arg_operands(), ValAssumedPoison)))
       return true;
   }
   return false;