[InstCombine] remove unnecessary vector select fold; NFCI

This code is double-dead:
1. We simplify all selects with constant true/false condition in InstSimplify.
   I've minimized/moved the tests to show that works as expected.
2. All remaining vector selects with a constant condition are canonicalized to
   shufflevector, so we really can't see this pattern.

llvm-svn: 312123

1 files changed, 0 insertions, 4 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index c43dad53704..11602ab101e 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1566,10 +1566,6 @@ Instruction *InstCombiner::visitSelectInst(SelectInst &SI) {
         return replaceInstUsesWith(SI, V);
       return &SI;
     }
-
-    if (isa<ConstantAggregateZero>(CondVal)) {
-      return replaceInstUsesWith(SI, FalseVal);
-    }
   }
 
   // See if we can determine the result of this select based on a dominating