[PATCH] D136835: [Clang][LoongArch] Support inline asm constraint 'J'

[Lu Weining via Phabricator via llvm-commits]

SixWeining created this revision.
SixWeining added reviewers: xen0n, xry111, MaskRay, wangleiat, gonglingqin.
Herald added subscribers: StephenFan, hiraditya.
Herald added a project: All.
SixWeining requested review of this revision.
Herald added projects: clang, LLVM.
Herald added subscribers: llvm-commits, cfe-commits.

'J' is defined in GCC [1] but not documented [2] while Linux [3] has
already used it in LoongArch port.

[1]: https://github.com/gcc-mirror/gcc/blob/master/gcc/config/loongarch/constraints.md#L61
[2]: https://gcc.gnu.org/onlinedocs/gccint/Machine-Constraints.html
[3]: https://github.com/torvalds/linux/blob/master/arch/loongarch/include/asm/cmpxchg.h#L19


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D136835

Files:
  clang/lib/Basic/Targets/LoongArch.cpp
  clang/test/CodeGen/LoongArch/inline-asm-constraints.c
  llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
  llvm/test/CodeGen/LoongArch/inline-asm-constraint-error.ll
  llvm/test/CodeGen/LoongArch/inline-asm-constraint.ll


Index: llvm/test/CodeGen/LoongArch/inline-asm-constraint.ll
===================================================================
--- llvm/test/CodeGen/LoongArch/inline-asm-constraint.ll
+++ llvm/test/CodeGen/LoongArch/inline-asm-constraint.ll
@@ -58,6 +58,17 @@
   ret void
 }
 
+define void @constraint_J() nounwind {
+; CHECK-LABEL: constraint_J:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    #APP
+; CHECK-NEXT:    addi.w $a0, $a0, 0
+; CHECK-NEXT:    #NO_APP
+; CHECK-NEXT:    ret
+  tail call void asm sideeffect "addi.w $$a0, $$a0, $0", "J"(i32 0)
+  ret void
+}
+
 define void @constraint_K() nounwind {
 ; CHECK-LABEL: constraint_K:
 ; CHECK:       # %bb.0:
Index: llvm/test/CodeGen/LoongArch/inline-asm-constraint-error.ll
===================================================================
--- llvm/test/CodeGen/LoongArch/inline-asm-constraint-error.ll
+++ llvm/test/CodeGen/LoongArch/inline-asm-constraint-error.ll
@@ -17,6 +17,12 @@
   ret void
 }
 
+define void @constraint_J() {
+; CHECK: error: value out of range for constraint 'J'
+  tail call void asm sideeffect "addi.w $$a0, $$a0, $$0", "J"(i32 1)
+  ret void
+}
+
 define void @constraint_K() {
 ; CHECK: error: value out of range for constraint 'K'
   tail call void asm sideeffect "andi.w $$a0, $$a0, $0", "K"(i32 4096)
Index: llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
===================================================================
--- llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
+++ llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
@@ -2169,6 +2169,7 @@
       return C_RegisterClass;
     case 'l':
     case 'I':
+    case 'J':
     case 'K':
       return C_Immediate;
     case 'k':
@@ -2272,6 +2273,13 @@
               DAG.getTargetConstant(CVal, SDLoc(Op), Subtarget.getGRLenVT()));
       }
       return;
+    case 'J':
+      // Validate & create an integer zero operand.
+      if (auto *C = dyn_cast<ConstantSDNode>(Op))
+        if (C->getZExtValue() == 0)
+          Ops.push_back(
+              DAG.getTargetConstant(0, SDLoc(Op), Subtarget.getGRLenVT()));
+      return;
     case 'K':
       // Validate & create a 12-bit unsigned immediate operand.
       if (auto *C = dyn_cast<ConstantSDNode>(Op)) {
Index: clang/test/CodeGen/LoongArch/inline-asm-constraints.c
===================================================================
--- clang/test/CodeGen/LoongArch/inline-asm-constraints.c
+++ clang/test/CodeGen/LoongArch/inline-asm-constraints.c
@@ -43,6 +43,12 @@
   asm volatile ("" :: "I"(-2048));
 }
 
+void test_J(void) {
+// CHECK-LABEL: define{{.*}} void @test_J()
+// CHECK: call void asm sideeffect "", "J"(i32 0)
+  asm volatile ("" :: "J"(0));
+}
+
 void test_K(void) {
 // CHECK-LABEL: define{{.*}} void @test_K()
 // CHECK: call void asm sideeffect "", "K"(i32 4095)
Index: clang/lib/Basic/Targets/LoongArch.cpp
===================================================================
--- clang/lib/Basic/Targets/LoongArch.cpp
+++ clang/lib/Basic/Targets/LoongArch.cpp
@@ -88,6 +88,10 @@
     // A signed 12-bit constant (for arithmetic instructions).
     Info.setRequiresImmediate(-2048, 2047);
     return true;
+  case 'J':
+    // Integer zero.
+    Info.setRequiresImmediate(0);
+    return true;
   case 'K':
     // An unsigned 12-bit constant (for logic instructions).
     Info.setRequiresImmediate(0, 4095);


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