[ARM] GlobalISel: Add reg bank mappings for G_SEQUENCE and G_EXTRACT

Support G_SEQUENCE and G_EXTRACT as needed for passing double precision floating
point values in the soft-fp float mode.

llvm-svn: 295306

2 files changed, 58 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMRegisterBankInfo.cpp b/llvm/lib/Target/ARM/ARMRegisterBankInfo.cpp
index 7af51c68b3a..193a85502e6 100644
--- a/llvm/lib/Target/ARM/ARMRegisterBankInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMRegisterBankInfo.cpp
@@ -143,6 +143,32 @@ ARMRegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
   case G_FRAME_INDEX:
     OperandsMapping = getOperandsMapping({&ARM::ValueMappings[0], nullptr});
     break;
+  case G_SEQUENCE: {
+    // We only support G_SEQUENCE for creating a double precision floating point
+    // value out of two GPRs.
+    LLT Ty1 = MRI.getType(MI.getOperand(1).getReg());
+    LLT Ty2 = MRI.getType(MI.getOperand(3).getReg());
+    if (Ty.getSizeInBits() != 64 || Ty1.getSizeInBits() != 32 ||
+        Ty2.getSizeInBits() != 32)
+      return InstructionMapping{};
+    OperandsMapping =
+        getOperandsMapping({&ARM::ValueMappings[6], &ARM::ValueMappings[0],
+                            nullptr, &ARM::ValueMappings[0], nullptr});
+    break;
+  }
+  case G_EXTRACT: {
+    // We only support G_EXTRACT for splitting a double precision floating point
+    // value into two GPRs.
+    LLT Ty1 = MRI.getType(MI.getOperand(1).getReg());
+    LLT Ty2 = MRI.getType(MI.getOperand(2).getReg());
+    if (Ty.getSizeInBits() != 32 || Ty1.getSizeInBits() != 32 ||
+        Ty2.getSizeInBits() != 64)
+      return InstructionMapping{};
+    OperandsMapping =
+        getOperandsMapping({&ARM::ValueMappings[0], &ARM::ValueMappings[0],
+                            &ARM::ValueMappings[6], nullptr, nullptr});
+    break;
+  }
   default:
     return InstructionMapping{};
   }
diff --git a/llvm/test/CodeGen/ARM/GlobalISel/arm-regbankselect.mir b/llvm/test/CodeGen/ARM/GlobalISel/arm-regbankselect.mir
index 7d3b6c23109..cc80634abd1 100644
--- a/llvm/test/CodeGen/ARM/GlobalISel/arm-regbankselect.mir
+++ b/llvm/test/CodeGen/ARM/GlobalISel/arm-regbankselect.mir
@@ -9,6 +9,8 @@
 
   define void @test_fadd_s32() { ret void }
   define void @test_fadd_s64() { ret void }
+
+  define void @test_soft_fp_s64() { ret void }
 ...
 ---
 name:            test_add_s32
@@ -202,5 +204,35 @@ body:             |
     BX_RET 14, _, implicit %d0
 
 ...
+---
+name:            test_soft_fp_s64
+# CHECK-LABEL: name: test_soft_fp_s64
+legalized:       true
+regBankSelected: false
+selected:        false
+# CHECK: registers:
+# CHECK: - { id: 0, class: gprb }
+# CHECK: - { id: 1, class: gprb }
+# CHECK: - { id: 2, class: fprb }
+# CHECK: - { id: 3, class: gprb }
+# CHECK: - { id: 4, class: gprb }
+
+registers:
+  - { id: 0, class: _ }
+  - { id: 1, class: _ }
+  - { id: 2, class: _ }
+  - { id: 3, class: _ }
+  - { id: 4, class: _ }
+body:             |
+  bb.0:
+    liveins: %r0, %r1
+
+    %0(s32) = COPY %r0
+    %1(s32) = COPY %r1
+    %2(s64) = G_SEQUENCE %0(s32), 0, %1(s32), 32
+    %3(s32), %4(s32) = G_EXTRACT %2(s64), 0, 32
+    %r0 = COPY %3(s32)
+    %r1 = COPY %4(s32)
+    BX_RET 14, _, implicit %r0, implicit %r1
 
 ...