[PATCH] D138100: [LoongArch] Implement assembler branches pseudo instructions

[wanglei via Phabricator via llvm-commits]

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These instructions always output the canonical mnemonic. The GNU tools
emit the canonical mnemonic for the branch pseudo instructions as well
(e.g. "bgt" will be recognised by the assembler but never printed by
objdump).


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D138100

Files:
  llvm/lib/Target/LoongArch/LoongArchInstrInfo.td
  llvm/test/MC/LoongArch/Macros/aliases-br.s


Index: llvm/test/MC/LoongArch/Macros/aliases-br.s
===================================================================
--- /dev/null
+++ llvm/test/MC/LoongArch/Macros/aliases-br.s
@@ -0,0 +1,18 @@
+# RUN: llvm-mc --triple=loongarch64 %s | FileCheck %s
+
+bgt   $a1, $a0, 16
+# CHECK:      blt     $a0, $a1, 16
+bgtu  $a1, $a0, 16
+# CHECK-NEXT: bltu    $a0, $a1, 16
+ble   $a1, $a0, 16
+# CHECK-NEXT: bge     $a0, $a1, 16
+bleu  $a1, $a0, 16
+# CHECK-NEXT: bgeu    $a0, $a1, 16
+bltz   $a0, 16
+# CHECK-NEXT: blt     $a0, $zero, 16
+bgtz   $a0, 16
+# CHECK-NEXT: blt     $zero, $a0, 16
+blez   $a0, 16
+# CHECK-NEXT: bge     $zero, $a0, 16
+bgez   $a0, 16
+# CHECK-NEXT: bge     $a0, $zero, 16
Index: llvm/lib/Target/LoongArch/LoongArchInstrInfo.td
===================================================================
--- llvm/lib/Target/LoongArch/LoongArchInstrInfo.td
+++ llvm/lib/Target/LoongArch/LoongArchInstrInfo.td
@@ -1348,6 +1348,28 @@
 def : InstAlias<"ret", (JIRL R0, R1, 0)>;
 def : InstAlias<"jr $rj", (JIRL R0, GPR:$rj, 0)>;
 
+// Branches implemented with alias.
+// Always output the canonical mnemonic for the pseudo branch instructions.
+// The GNU tools emit the canonical mnemonic for the branch pseudo instructions
+// as well (e.g. "bgt" will be recognised by the assembler but never printed by
+// objdump). Match this behaviour by setting a zero weight.
+def : InstAlias<"bgt $rj, $rd, $imm16",
+                (BLT GPR:$rd, GPR:$rj, simm16_lsl2_br:$imm16), 0>;
+def : InstAlias<"bgtu $rj, $rd, $imm16",
+                (BLTU GPR:$rd, GPR:$rj, simm16_lsl2_br:$imm16), 0>;
+def : InstAlias<"ble $rj, $rd, $imm16",
+                (BGE GPR:$rd, GPR:$rj, simm16_lsl2_br:$imm16), 0>;
+def : InstAlias<"bleu $rj, $rd, $imm16",
+                (BGEU GPR:$rd, GPR:$rj, simm16_lsl2_br:$imm16), 0>;
+def : InstAlias<"bltz $rd, $imm16",
+                (BLT GPR:$rd, R0, simm16_lsl2_br:$imm16), 0>;
+def : InstAlias<"bgtz $rj, $imm16",
+                (BLT R0, GPR:$rj, simm16_lsl2_br:$imm16), 0>;
+def : InstAlias<"blez $rj, $imm16",
+                (BGE R0, GPR:$rj, simm16_lsl2_br:$imm16), 0>;
+def : InstAlias<"bgez $rd, $imm16",
+                (BGE GPR:$rd, R0, simm16_lsl2_br:$imm16), 0>;
+
 //===----------------------------------------------------------------------===//
 // Basic Floating-Point Instructions
 //===----------------------------------------------------------------------===//


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