[AArch64][GlobalISel] Zero-extend s1 values when returning.

Before we were relying on the any extend of the s1 to s32, but
for AAPCS we need to zero-extend it to at least s8.

Fixes PR36719

Differential Revision: https://reviews.llvm.org/D47425

llvm-svn: 333747
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index b5cc7f7..87086af 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -726,17 +726,7 @@
         WideTy != LLT::scalar(8))
       return UnableToLegalize;
 
-    const auto &TLI = *MIRBuilder.getMF().getSubtarget().getTargetLowering();
-    switch (TLI.getBooleanContents(false, false)) {
-    case TargetLoweringBase::ZeroOrNegativeOneBooleanContent:
-      widenScalarSrc(MI, WideTy, 0, TargetOpcode::G_SEXT);
-      break;
-    case TargetLoweringBase::ZeroOrOneBooleanContent:
-      widenScalarSrc(MI, WideTy, 0, TargetOpcode::G_ZEXT);
-      break;
-    default:
-      widenScalarSrc(MI, WideTy, 0, TargetOpcode::G_ANYEXT);
-    }
+    widenScalarSrc(MI, WideTy, 0, TargetOpcode::G_ZEXT);
     MIRBuilder.recordInsertion(&MI);
     return Legalized;
   }