[llvm] r276952 - [InstCombine] Handle failures from ConstantFoldConstantExpression

[David Majnemer via llvm-commits]

Author: majnemer
Date: Wed Jul 27 21:29:06 2016
New Revision: 276952

URL: http://llvm.org/viewvc/llvm-project?rev=276952&view=rev
Log:
[InstCombine] Handle failures from ConstantFoldConstantExpression

ConstantFoldConstantExpression returns null when folding fails.

This fixes PR28745.

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp
    llvm/trunk/test/Transforms/InstCombine/cast.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp?rev=276952&r1=276951&r2=276952&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp Wed Jul 27 21:29:06 2016
@@ -162,7 +162,8 @@ Value *InstCombiner::EvaluateInDifferent
     C = ConstantExpr::getIntegerCast(C, Ty, isSigned /*Sext or ZExt*/);
     // If we got a constantexpr back, try to simplify it with DL info.
     if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
-      C = ConstantFoldConstantExpression(CE, DL, TLI);
+      if (Constant *FoldedC = ConstantFoldConstantExpression(CE, DL, TLI))
+        C = FoldedC;
     return C;
   }
 

Modified: llvm/trunk/test/Transforms/InstCombine/cast.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/cast.ll?rev=276952&r1=276951&r2=276952&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/cast.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/cast.ll Wed Jul 27 21:29:06 2016
@@ -1372,3 +1372,11 @@ define i16 @PR24763(i8 %V) {
   %t = trunc i32 %l to i16
   ret i16 %t
 }
+
+define i64 @PR28745() {
+; CHECK-LABEL: @PR28745(
+; CHECK-NEXT:    ret i64 zext (i32 extractvalue ({ i32 } select (i1 icmp eq (i16 extractelement (<2 x i16> bitcast (<1 x i32> <i32 1> to <2 x i16>), i32 0), i16 0), { i32 } { i32 1 }, { i32 } zeroinitializer), 0) to i64)
+
+  %b = zext i32 extractvalue ({ i32 } select (i1 icmp eq (i16 extractelement (<2 x i16> bitcast (<1 x i32> <i32 1> to <2 x i16>), i32 0), i16 0), { i32 } { i32 1 }, { i32 } zeroinitializer), 0) to i64
+  ret i64 %b
+}