[ARM] Lower modulo operation to generate __aeabi_divmod on Android

    
For a modulo (reminder) operation,
clang -target armv7-none-linux-gnueabi generates "__modsi3"
clang -target armv7-none-eabi generates "__aeabi_idivmod"
clang -target armv7-linux-androideabi generates "__modsi3"
Android bionic libc doesn't provide a __modsi3, instead it provides a
"__aeabi_idivmod". This patch fixes the LLVM ARMISelLowering to generate
the correct call when ever there is a modulo operation.

Differential Revision: http://reviews.llvm.org/D11661

llvm-svn: 243717

llvm/lib/Target/ARM/ARMISelLowering.cpp

@@ -735,11 +735,11 @@ ARMTargetLowering::ARMTargetLowering(const TargetMachine &TM,
     setOperationAction(ISD::UDIV,  MVT::i32, Expand);
   }
 
-  // FIXME: Also set divmod for SREM on EABI
+  // FIXME: Also set divmod for SREM on EABI/androideabi
   setOperationAction(ISD::SREM,  MVT::i32, Expand);
   setOperationAction(ISD::UREM,  MVT::i32, Expand);
   // Register based DivRem for AEABI (RTABI 4.2)
-  if (Subtarget->isTargetAEABI()) {
+  if (Subtarget->isTargetAEABI() || Subtarget->isTargetAndroid()) {
     setLibcallName(RTLIB::SDIVREM_I8,  "__aeabi_idivmod");
     setLibcallName(RTLIB::SDIVREM_I16, "__aeabi_idivmod");
     setLibcallName(RTLIB::SDIVREM_I32, "__aeabi_idivmod");
@@ -11159,7 +11159,8 @@ void ARMTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
 }
 
 SDValue ARMTargetLowering::LowerDivRem(SDValue Op, SelectionDAG &DAG) const {
-  assert(Subtarget->isTargetAEABI() && "Register-based DivRem lowering only");
+  assert((Subtarget->isTargetAEABI() || Subtarget->isTargetAndroid()) &&
+         "Register-based DivRem lowering only");
   unsigned Opcode = Op->getOpcode();
   assert((Opcode == ISD::SDIVREM || Opcode == ISD::UDIVREM) &&
          "Invalid opcode for Div/Rem lowering");

llvm/test/CodeGen/ARM/divmod-eabi.ll

@@ -1,5 +1,7 @@
 ; RUN: llc -mtriple armv7-none-eabi %s -o - | FileCheck %s --check-prefix=EABI
 ; RUN: llc -mtriple armv7-none-eabihf %s -o - | FileCheck %s --check-prefix=EABI
+; Both "none-eabi" and "androideabi" must lower SREM/UREM to __aeabi_{u,i}divmod
+; RUN: llc -mtriple armv7-linux-androideabi %s -o - | FileCheck %s --check-prefix=EABI
 ; RUN: llc -mtriple armv7-linux-gnueabi %s -o - | FileCheck %s --check-prefix=GNU
 ; RUN: llc -mtriple armv7-apple-darwin %s -o - | FileCheck %s --check-prefix=DARWIN
 ; FIXME: long-term, we will use "-apple-macho" and won't need this exception: