From ca25d25d4c5131491a50b1a94e63e9b2d3c34ed4 Mon Sep 17 00:00:00 2001
From: Richard-Qin-X <richard.qin.001@gmail.com>
Date: Sun, 16 Aug 2026 16:13:12 +0800
Subject: [RISCV][GlobalISel] Select comparisons against zero

---
 backend/lib/Target/RISCV/RISCVGISel.rccdesc | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'backend/lib/Target')

diff --git a/backend/lib/Target/RISCV/RISCVGISel.rccdesc b/backend/lib/Target/RISCV/RISCVGISel.rccdesc
index 97ed3d6..bd946be 100644
--- a/backend/lib/Target/RISCV/RISCVGISel.rccdesc
+++ b/backend/lib/Target/RISCV/RISCVGISel.rccdesc
@@ -155,3 +155,24 @@ selection_rules:
         - { index: 0, bank: GPR }
         - { index: 1, bank: FPR }
     apply: { opcode: FCLASS_D }
+  -
+    id: select_g_icmp_ne_zero
+    priority: 200
+    match:
+      opcode: G_ICMP
+      result_type: { kind: scalar, bits: 64 }
+      integer_predicate: { index: 1, value: ne }
+      operand_types:
+        - { index: 2, kind: scalar, bits: 64 }
+      operand_banks:
+        - { index: 0, bank: GPR }
+        - { index: 2, bank: GPR }
+      operand_def_constants:
+        - { index: 3, value: 0 }
+    apply:
+      opcode: SLTU
+      operands:
+        - { operand: 0 }
+        - { physical_register: X0, flags: [use] }
+        - { operand: 2 }
+      erase_operand_definitions: [3]
-- 
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