Make sure to initialize local variables, even if they were ignored by

ABI.

llvm-svn: 64187

2 files changed, 21 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index fbc421cb9e6..f90d31cd0b0 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -1266,6 +1266,13 @@ void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI,
     }
 
     case ABIArgInfo::Ignore:
+      // Initialize the local variable appropriately.
+      if (hasAggregateLLVMType(Ty)) { 
+        EmitParmDecl(*Arg, CreateTempAlloca(ConvertType(Ty)));
+      } else {
+        EmitParmDecl(*Arg, llvm::UndefValue::get(ConvertType(Arg->getType())));
+      }
+      
       // Skip increment, no matching LLVM parameter.
       continue; 
 
diff --git a/clang/test/CodeGen/parameter-passing.c b/clang/test/CodeGen/parameter-passing.c
index 637a2de42c8..5cc5e4797ca 100644
--- a/clang/test/CodeGen/parameter-passing.c
+++ b/clang/test/CodeGen/parameter-passing.c
@@ -1,6 +1,9 @@
 // Check the various ways in which the three classes of values
 // (scalar, complex, aggregate) interact with parameter passing
 // (function entry, function return, call argument, call result).
+//
+// We also check _Bool and empty structures, as these can have annoying
+// corner cases.
 
 // RUN: clang %s -triple i386-unknown-unknown -O3 -emit-llvm -o %t &&
 // RUN: not grep '@g0' %t &&
@@ -13,18 +16,26 @@
 // RUN: not grep '@g0' %t &&
 // RUN: true
 
+typedef _Bool BoolTy;
 typedef int ScalarTy;
 typedef _Complex int ComplexTy;
 typedef struct { int a, b, c; } AggrTy;
+typedef struct { int a[0]; } EmptyTy;
 
 static int result;
 
+static BoolTy bool_id(BoolTy a) { return a; }
 static AggrTy aggr_id(AggrTy a) { return a; }
+static EmptyTy empty_id(EmptyTy a) { return a; }
 static ScalarTy scalar_id(ScalarTy a) { return a; }
 static ComplexTy complex_id(ComplexTy a) { return a; }
 
+static void bool_mul(BoolTy a) { result *= a; }
+
 static void aggr_mul(AggrTy a) { result *= a.a * a.b * a.c; }
 
+static void empty_mul(EmptyTy a) { result *= 53; }
+
 static void scalar_mul(ScalarTy a) { result *= a; }
 
 static void complex_mul(ComplexTy a) { result *= __real a * __imag a; }
@@ -34,12 +45,14 @@ extern void g0(void);
 void f0(void) {
   result = 1;
   
+  bool_mul(bool_id(1));
   aggr_mul(aggr_id((AggrTy) { 2, 3, 5}));
+  empty_mul(empty_id((EmptyTy) {}));
   scalar_mul(scalar_id(7));
   complex_mul(complex_id(11 + 13i));
   
   // This call should be eliminated.
-  if (result != 30030)
+  if (result != 2 * 3 * 5 * 7 * 11 * 13 * 53)
     g0();
 }