From 3cf991146dca6b3cf6b7b17d3041c06145a3ef45 Mon Sep 17 00:00:00 2001
From: liyunfei <liyunfei33@huawei.com>
Date: Tue, 4 Jul 2023 17:10:09 +0800
Subject: [PATCH] [Backport][RISCV] Handle "o" inline asm memory constraint

Reference: https://reviews.llvm.org/rG26e41a80d07c

Originally By: wangpc <pc.wang@linux.alibaba.com>

This is the same as D100412.

We just found the same crash when we tried to compile some packages
like mariadb, php, etc.

For constraint "o", it means "A memory operand is allowed, but
only if the address is offsettable". So I think it can be handled
just like constraint "m" for RISCV target.

And we print verbose information when unsupported constraints occur.

Reviewed By: asb
---
 llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp |  4 +-
 llvm/test/CodeGen/RISCV/inline-asm.ll       | 72 +++++++++++++++++++++
 2 files changed, 75 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp b/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
index d5826b46d738..a98dcea7dd8d 100644
--- a/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
@@ -1733,6 +1733,7 @@ void RISCVDAGToDAGISel::Select(SDNode *Node) {
 bool RISCVDAGToDAGISel::SelectInlineAsmMemoryOperand(
     const SDValue &Op, unsigned ConstraintID, std::vector<SDValue> &OutOps) {
   switch (ConstraintID) {
+  case InlineAsm::Constraint_o:
   case InlineAsm::Constraint_m:
     // We just support simple memory operands that have a single address
     // operand and need no special handling.
@@ -1742,7 +1743,8 @@ bool RISCVDAGToDAGISel::SelectInlineAsmMemoryOperand(
     OutOps.push_back(Op);
     return false;
   default:
-    break;
+    report_fatal_error("Unexpected asm memory constraint " +
+                       InlineAsm::getMemConstraintName(ConstraintID));
   }
 
   return true;
diff --git a/llvm/test/CodeGen/RISCV/inline-asm.ll b/llvm/test/CodeGen/RISCV/inline-asm.ll
index 0b04a7df2d18..feaa40b14e9d 100644
--- a/llvm/test/CodeGen/RISCV/inline-asm.ll
+++ b/llvm/test/CodeGen/RISCV/inline-asm.ll
@@ -82,6 +82,78 @@ define i32 @constraint_m2(i32* %a) nounwind {
   ret i32 %1
 }
 
+define i32 @constraint_m_with_offset(ptr %a) nounwind {
+; RV32I-LABEL: constraint_m_with_offset:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    #APP
+; RV32I-NEXT:    lw a0, 4(a0)
+; RV32I-NEXT:    #NO_APP
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: constraint_m_with_offset:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    #APP
+; RV64I-NEXT:    lw a0, 4(a0)
+; RV64I-NEXT:    #NO_APP
+; RV64I-NEXT:    ret
+  %1 = getelementptr i32, ptr %a, i32 1
+  %2 = tail call i32 asm "lw $0, $1", "=r,*m"(ptr elementtype(i32) %1)
+  ret i32 %2
+}
+
+define void @constraint_o(ptr %a) nounwind {
+; RV32I-LABEL: constraint_o:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    #APP
+; RV32I-NEXT:    #NO_APP
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: constraint_o:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    #APP
+; RV64I-NEXT:    #NO_APP
+; RV64I-NEXT:    ret
+  call void asm sideeffect "", "=*o"(ptr elementtype(i32) %a)
+  ret void
+}
+
+define i32 @constraint_o2(ptr %a) nounwind {
+; RV32I-LABEL: constraint_o2:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    #APP
+; RV32I-NEXT:    lw a0, 0(a0)
+; RV32I-NEXT:    #NO_APP
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: constraint_o2:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    #APP
+; RV64I-NEXT:    lw a0, 0(a0)
+; RV64I-NEXT:    #NO_APP
+; RV64I-NEXT:    ret
+  %1 = tail call i32 asm "lw $0, $1", "=r,*o"(ptr elementtype(i32) %a)
+  ret i32 %1
+}
+
+define i32 @constraint_o_with_offset(ptr %a) nounwind {
+; RV32I-LABEL: constraint_o_with_offset:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    #APP
+; RV32I-NEXT:    lw a0, 4(a0)
+; RV32I-NEXT:    #NO_APP
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: constraint_o_with_offset:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    #APP
+; RV64I-NEXT:    lw a0, 4(a0)
+; RV64I-NEXT:    #NO_APP
+; RV64I-NEXT:    ret
+  %1 = getelementptr i32, ptr %a, i32 1
+  %2 = tail call i32 asm "lw $0, $1", "=r,*o"(ptr elementtype(i32) %1)
+  ret i32 %2
+}
+
 define void @constraint_I() nounwind {
 ; RV32I-LABEL: constraint_I:
 ; RV32I:       # %bb.0:
-- 
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