[AVR] Fix broken bitcast for aliases in non-zero address space

This was triggered by some code in picolibc. The minimal version looks
like this:

    double infinity(void) {
       return 5;
    }

    extern long double infinityl() __attribute__((__alias__("infinity")));

These two declarations have a different type (not because of the 'long
double', which is also 'double' in IR, but because infinityl has
variadic parameters). This led to a crash in the bitcast which assumed
address space 0.

Differential Revision: https://reviews.llvm.org/D138681

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index ae25767..133c603 100644 (file)
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -4002,7 +4002,8 @@ llvm::Constant *CodeGenModule::GetOrCreateLLVMFunction(
     // (If function is requested for a definition, we always need to create a new
     // function, not just return a bitcast.)
     if (!IsForDefinition)
-      return llvm::ConstantExpr::getBitCast(Entry, Ty->getPointerTo());
+      return llvm::ConstantExpr::getBitCast(
+          Entry, Ty->getPointerTo(Entry->getAddressSpace()));
   }
 
   // This function doesn't have a complete type (for example, the return

diff --git a/clang/test/CodeGen/avr/alias-avr.c b/clang/test/CodeGen/avr/alias-avr.c
index 88ba3a9..bcef98a 100644 (file)
--- a/clang/test/CodeGen/avr/alias-avr.c
+++ b/clang/test/CodeGen/avr/alias-avr.c
@@ -6,3 +6,8 @@ int mul(int a, int b) {
 
 // CHECK: @multiply ={{.*}} alias i16 (i16, i16), ptr addrspace(1) @mul
 int multiply(int x, int y) __attribute__((alias("mul")));
+
+// Make sure the correct address space is used when creating an alias that needs
+// a pointer cast.
+// CHECK: @smallmul = alias i8 (i16, i16), ptr addrspace(1) @mul
+char smallmul(int a, int b) __attribute__((alias("mul")));