[GlobalISel][IRTranslator] Fix a bug in handling repeating struct types during argument lowering.

Differential Revision: https://reviews.llvm.org/D49442

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339674 91177308-0d34-0410-b5e6-96231b3b80d8

Author: aemerson

include/llvm/CodeGen/GlobalISel/IRTranslator.h

@@ -232,6 +232,7 @@ class IRTranslator : public MachineFunctionPass {
 
   /// Returns true if the value should be split into multiple LLTs.
   /// If \p Offsets is given then the split type's offsets will be stored in it.
+  /// If \p Offsets is not empty it will be cleared first.
   bool valueIsSplit(const Value &V,
                     SmallVectorImpl<uint64_t> *Offsets = nullptr);
 

lib/CodeGen/GlobalISel/IRTranslator.cpp

@@ -1457,6 +1457,8 @@ void IRTranslator::finishPendingPhis() {
 bool IRTranslator::valueIsSplit(const Value &V,
                                 SmallVectorImpl<uint64_t> *Offsets) {
   SmallVector<LLT, 4> SplitTys;
+  if (Offsets && !Offsets->empty())
+    Offsets->clear();
   computeValueLLTs(*DL, *V.getType(), SplitTys, Offsets);
   return SplitTys.size() > 1;
 }

test/CodeGen/AArch64/GlobalISel/irtranslator-duplicate-types-param.ll

@@ -0,0 +1,15 @@
+; RUN: llc -O0 -o - -verify-machineinstrs %s | FileCheck %s
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-unknown-linux-gnu"
+
+; Check we don't crash due to encountering the same struct param type twice.
+; CHECK-LABEL: param_two_struct
+; CHECK: add
+; CHECK: ret
+define i64 @param_two_struct([2 x i64] %t.coerce, [2 x i64] %s.coerce) {
+entry:
+  %t.coerce.fca.0.extract = extractvalue [2 x i64] %t.coerce, 0
+  %s.coerce.fca.1.extract = extractvalue [2 x i64] %s.coerce, 1
+  %add = add nsw i64 %s.coerce.fca.1.extract, %t.coerce.fca.0.extract
+  ret i64 %add
+}