[MSP430] Generate EABI-compliant libcalls

Updates the MSP430 target to generate EABI-compatible libcall names.
As a byproduct, adjusts the hardware multiplier options available in
the MSP430 target, adds support for promotion of the ISD::MUL operation
for 8-bit integers, and correctly marks R11 as used by call instructions.

Patch by Andrew Wygle.

Differential Revision: https://reviews.llvm.org/D32676

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302820 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/IR/CallingConv.h

@@ -201,6 +201,10 @@ namespace CallingConv {
     /// shaders)
     AMDGPU_HS = 93,
 
+    /// Calling convention used for special MSP430 rtlib functions
+    /// which have an "optimized" convention using additional registers.
+    MSP430_BUILTIN = 94,
+
     /// The highest possible calling convention ID. Must be some 2^k - 1.
     MaxID = 1023
   };

lib/CodeGen/SelectionDAG/LegalizeDAG.cpp

@@ -4187,6 +4187,7 @@ void SelectionDAGLegalize::PromoteNode(SDNode *Node) {
     ReplacedNode(Node);
     break;
   }
+  case ISD::MUL:
   case ISD::SDIV:
   case ISD::SREM:
   case ISD::UDIV:

lib/Target/MSP430/MSP430InstrInfo.td

@@ -210,7 +210,7 @@ let isCall = 1 in
   // a use to prevent stack-pointer assignments that appear immediately
   // before calls from potentially appearing dead. Uses for argument
   // registers are added manually.
-  let Defs = [R12, R13, R14, R15, SR],
+  let Defs = [R11, R12, R13, R14, R15, SR],
       Uses = [SP] in {
     def CALLi     : II16i<0x0,
                           (outs), (ins i16imm:$dst),

lib/Target/MSP430/MSP430RegisterInfo.cpp

@@ -41,12 +41,12 @@ MSP430RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
   const Function* F = MF->getFunction();
   static const MCPhysReg CalleeSavedRegs[] = {
     MSP430::FP, MSP430::R5, MSP430::R6, MSP430::R7,
-    MSP430::R8, MSP430::R9, MSP430::R10, MSP430::R11,
+    MSP430::R8, MSP430::R9, MSP430::R10,
     0
   };
   static const MCPhysReg CalleeSavedRegsFP[] = {
     MSP430::R5, MSP430::R6, MSP430::R7,
-    MSP430::R8, MSP430::R9, MSP430::R10, MSP430::R11,
+    MSP430::R8, MSP430::R9, MSP430::R10,
     0
   };
   static const MCPhysReg CalleeSavedRegsIntr[] = {

test/CodeGen/MSP430/hwmult16.ll

@@ -0,0 +1,43 @@
+; RUN: llc -O0 -mhwmult=16bit < %s | FileCheck %s
+
+target datalayout = "e-p:16:16:16-i8:8:8-i16:16:16-i32:16:32-n8:16-a0:16:16"
+target triple = "msp430---elf"
+
+@g_i32 = global i32 123, align 8
+@g_i64 = global i64 456, align 8
+@g_i16 = global i16 789, align 8
+
+define i16 @mpyi() #0 {
+entry:
+; CHECK: mpyi:
+
+; CHECK: call #__mspabi_mpyi_hw
+  %0 = load volatile i16, i16* @g_i16, align 8
+  %1 = mul i16 %0, %0
+
+  ret i16 %1
+}
+
+define i32 @mpyli() #0 {
+entry:
+; CHECK: mpyli:
+
+; CHECK: call #__mspabi_mpyl_hw
+  %0 = load volatile i32, i32* @g_i32, align 8
+  %1 = mul i32 %0, %0
+
+  ret i32 %1
+}
+
+define i64 @mpylli() #0 {
+entry:
+; CHECK: mpylli:
+
+; CHECK: call #__mspabi_mpyll_hw
+  %0 = load volatile i64, i64* @g_i64, align 8
+  %1 = mul i64 %0, %0
+
+  ret i64 %1
+}
+
+attributes #0 = { nounwind }

test/CodeGen/MSP430/hwmult32.ll

@@ -0,0 +1,43 @@
+; RUN: llc -O0 -mhwmult=32bit < %s | FileCheck %s
+
+target datalayout = "e-p:16:16:16-i8:8:8-i16:16:16-i32:16:32-n8:16-a0:16:16"
+target triple = "msp430---elf"
+
+@g_i32 = global i32 123, align 8
+@g_i64 = global i64 456, align 8
+@g_i16 = global i16 789, align 8
+
+define i16 @mpyi() #0 {
+entry:
+; CHECK: mpyi:
+
+; CHECK: call #__mspabi_mpyi_hw
+  %0 = load volatile i16, i16* @g_i16, align 8
+  %1 = mul i16 %0, %0
+
+  ret i16 %1
+}
+
+define i32 @mpyli() #0 {
+entry:
+; CHECK: mpyli:
+
+; CHECK: call #__mspabi_mpyl_hw32
+  %0 = load volatile i32, i32* @g_i32, align 8
+  %1 = mul i32 %0, %0
+
+  ret i32 %1
+}
+
+define i64 @mpylli() #0 {
+entry:
+; CHECK: mpylli:
+
+; CHECK: call #__mspabi_mpyll_hw32
+  %0 = load volatile i64, i64* @g_i64, align 8
+  %1 = mul i64 %0, %0
+
+  ret i64 %1
+}
+
+attributes #0 = { nounwind }

test/CodeGen/MSP430/hwmultf5.ll

@@ -0,0 +1,43 @@
+; RUN: llc -O0 -mhwmult=f5series < %s | FileCheck %s
+
+target datalayout = "e-p:16:16:16-i8:8:8-i16:16:16-i32:16:32-n8:16-a0:16:16"
+target triple = "msp430---elf"
+
+@g_i32 = global i32 123, align 8
+@g_i64 = global i64 456, align 8
+@g_i16 = global i16 789, align 8
+
+define i16 @mpyi() #0 {
+entry:
+; CHECK: mpyi:
+
+; CHECK: call #__mspabi_mpyi_f5hw
+  %0 = load volatile i16, i16* @g_i16, align 8
+  %1 = mul i16 %0, %0
+
+  ret i16 %1
+}
+
+define i32 @mpyli() #0 {
+entry:
+; CHECK: mpyli:
+
+; CHECK: call #__mspabi_mpyl_f5hw
+  %0 = load volatile i32, i32* @g_i32, align 8
+  %1 = mul i32 %0, %0
+
+  ret i32 %1
+}
+
+define i64 @mpylli() #0 {
+entry:
+; CHECK: mpylli:
+
+; CHECK: call #__mspabi_mpyll_f5hw
+  %0 = load volatile i64, i64* @g_i64, align 8
+  %1 = mul i64 %0, %0
+
+  ret i64 %1
+}
+
+attributes #0 = { nounwind }

test/CodeGen/MSP430/jumptable.ll

@@ -12,7 +12,7 @@ entry:
   store i16 %i, i16* %i.addr, align 2
   %0 = load i16, i16* %i.addr, align 2
 ; CHECK: mov.w #2, r13
-; CHECK: call #__mulhi3hw_noint
+; CHECK: call #__mspabi_mpyi
 ; CHECK: br .LJTI0_0(r12)
   switch i16 %0, label %sw.default [
     i16 0, label %sw.bb