[clang] Do not extend i8 return values to i16 on AVR.

Reviewed By: Miss_Grape, aykevl

Differential Revision: https://reviews.llvm.org/D139908

diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index 98b54df..aec170a 100644 (file)
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -8445,6 +8445,10 @@ public:
       LargeRet = true;
       return getNaturalAlignIndirect(Ty);
     }
+    // An i8 return value should not be extended to i16, since AVR has 8-bit
+    // registers.
+    if (Ty->isIntegralOrEnumerationType() && getContext().getTypeSize(Ty) <= 8)
+      return ABIArgInfo::getDirect();
     // Otherwise we follow the default way which is compatible.
     return DefaultABIInfo::classifyReturnType(Ty);
   }

diff --git a/clang/test/CodeGen/avr/avr-builtins.c b/clang/test/CodeGen/avr/avr-builtins.c
index bdecff3..7c2c424 100644 (file)
--- a/clang/test/CodeGen/avr/avr-builtins.c
+++ b/clang/test/CodeGen/avr/avr-builtins.c
@@ -8,7 +8,7 @@ unsigned char bitrev8(unsigned char data) {
     return __builtin_bitreverse8(data);
 }
 
-// CHECK: define{{.*}} zeroext i8 @bitrev8
+// CHECK: define{{.*}} i8 @bitrev8
 // CHECK: i8 @llvm.bitreverse.i8(i8
 
 unsigned int bitrev16(unsigned int data) {
@@ -35,7 +35,7 @@ unsigned char rotleft8(unsigned char x, unsigned char y) {
     return __builtin_rotateleft8(x, y);
 }
 
-// CHECK: define{{.*}} zeroext i8 @rotleft8
+// CHECK: define{{.*}} i8 @rotleft8
 // CHECK: i8 @llvm.fshl.i8(i8
 
 unsigned int rotleft16(unsigned int x, unsigned int y) {
@@ -62,7 +62,7 @@ unsigned char rotright8(unsigned char x, unsigned char y) {
     return __builtin_rotateright8(x, y);
 }
 
-// CHECK: define{{.*}} zeroext i8 @rotright8
+// CHECK: define{{.*}} i8 @rotright8
 // CHECK: i8 @llvm.fshr.i8(i8
 
 unsigned int rotright16(unsigned int x, unsigned int y) {