Add a new icmp+select optz'n. Also shows off the load(cst) folding added in

r140966.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140969 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/InstCombine/InstCombineSelect.cpp b/lib/Transforms/InstCombine/InstCombineSelect.cpp
index ae42d526ae71a22923ec468330304c8136e55a48..91e60a4fb24418639c7094447f78a5d7199935b0 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -482,10 +482,16 @@ Instruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI,
     if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, TD) == TrueVal ||
         SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, TD) == TrueVal)
       return ReplaceInstUsesWith(SI, FalseVal);
+    if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, TD) == FalseVal ||
+        SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, TD) == FalseVal)
+      return ReplaceInstUsesWith(SI, FalseVal);
   } else if (Pred == ICmpInst::ICMP_NE) {
     if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, TD) == FalseVal ||
         SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, TD) == FalseVal)
       return ReplaceInstUsesWith(SI, TrueVal);
+    if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, TD) == TrueVal ||
+        SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, TD) == TrueVal)
+      return ReplaceInstUsesWith(SI, TrueVal);
   }
 
   // NOTE: if we wanted to, this is where to detect integer MIN/MAX

diff --git a/test/Transforms/InstCombine/select.ll b/test/Transforms/InstCombine/select.ll
index 4ca9bd2c07c08a9bab3315c76623e51a5fd34bba..46615613eb9c077ddab6119c591e71d79e5bc73f 100644 (file)
--- a/test/Transforms/InstCombine/select.ll
+++ b/test/Transforms/InstCombine/select.ll
@@ -799,3 +799,13 @@ define i1 @test60(i32 %x, i1* %y) nounwind {
 ; CHECK: @test60
 ; CHECK: select
 }
+
+@glbl = constant i32 10
+define i32 @test61(i32* %ptr) {
+  %A = load i32* %ptr
+  %B = icmp eq i32* %ptr, @glbl
+  %C = select i1 %B, i32 %A, i32 10
+  ret i32 %C
+; CHECK: @test61
+; CHECK: ret i32 10
+}