Teach DataLayout that ABI alignments for non-aggregate types must be non-zero.

This manifested as assertions and/or crashes in later phases of optimization,
depending on the build configuration.

llvm-svn: 230939

llvm/lib/IR/DataLayout.cpp

@@ -312,6 +312,9 @@ void DataLayout::parseSpecifier(StringRef Desc) {
             "Missing alignment specification in datalayout string");
       Split = split(Rest, ':');
       unsigned ABIAlign = inBytes(getInt(Tok));
+      if (AlignType != AGGREGATE_ALIGN && !ABIAlign)
+        report_fatal_error(
+            "ABI alignment specification must be >0 for non-aggregate types");
 
       // Preferred alignment.
       unsigned PrefAlign = ABIAlign;

llvm/test/Assembler/invalid-datalayout22.ll

@@ -0,0 +1,6 @@
+; RUN: not llvm-as < %s 2>&1 | FileCheck %s
+
+target datalayout = "v128:0:128"
+
+; CHECK: ABI alignment specification must be >0 for non-aggregate types
+