[LoongArch] Don't merge FrameIndex accesses into [F]{LD,ST}X

Otherwise eliminateFrameIndex cannot figure out how to fixup the stack offset with its stateless logic, because there wouldn't be an immediate slot for it to trivially write to, and it may not be easy to transform the surrounding code to make it work. This fixes a fairly common crash when compiling moderately complex code with Clang. Differential Revision: https://reviews.llvm.org/D135251
llvm · Oct 9, 2022 · 31327c2 · 31327c2
1 parent f204229
commit 31327c2
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Showing 7 changed files with 128 additions and 4 deletions.
diff --git a/llvm/lib/Target/LoongArch/LoongArchISelDAGToDAG.cpp b/llvm/lib/Target/LoongArch/LoongArchISelDAGToDAG.cpp
@@ -88,6 +88,14 @@ bool LoongArchDAGToDAGISel::SelectBaseAddr(SDValue Addr, SDValue &Base) {
   return true;
 }
 
+bool LoongArchDAGToDAGISel::selectNonFIBaseAddr(SDValue Addr, SDValue &Base) {
+  // If this is FrameIndex, don't select it.
+  if (isa<FrameIndexSDNode>(Addr))
+    return false;
+  Base = Addr;
+  return true;
+}
+
 bool LoongArchDAGToDAGISel::selectShiftMask(SDValue N, unsigned ShiftWidth,
                                             SDValue &ShAmt) {
   // Shift instructions on LoongArch only read the lower 5 or 6 bits of the

diff --git a/llvm/lib/Target/LoongArch/LoongArchISelDAGToDAG.h b/llvm/lib/Target/LoongArch/LoongArchISelDAGToDAG.h
@@ -39,6 +39,7 @@ class LoongArchDAGToDAGISel : public SelectionDAGISel {
   void Select(SDNode *Node) override;
 
   bool SelectBaseAddr(SDValue Addr, SDValue &Base);
+  bool selectNonFIBaseAddr(SDValue Addr, SDValue &Base);
 
   bool selectShiftMask(SDValue N, unsigned ShiftWidth, SDValue &ShAmt);
   bool selectShiftMaskGRLen(SDValue N, SDValue &ShAmt) {

diff --git a/llvm/lib/Target/LoongArch/LoongArchInstrInfo.td b/llvm/lib/Target/LoongArch/LoongArchInstrInfo.td
@@ -248,6 +248,7 @@ def ImmSubFrom32 : SDNodeXForm<imm, [{
 }]>;
 
 def BaseAddr : ComplexPattern<iPTR, 1, "SelectBaseAddr">;
+def NonFIBaseAddr : ComplexPattern<iPTR, 1, "selectNonFIBaseAddr">;
 
 def fma_nsz : PatFrag<(ops node:$fj, node:$fk, node:$fa),
                       (fma node:$fj, node:$fk, node:$fa), [{
@@ -987,8 +988,8 @@ defm : LdPat<load, LD_D, i64>;
 // LA64 register-register-addressed loads
 let Predicates = [IsLA64] in {
 class RegRegLdPat<PatFrag LoadOp, LAInst Inst, ValueType vt>
-  : Pat<(vt (LoadOp (add BaseAddr:$rj, GPR:$rk))),
-        (Inst BaseAddr:$rj, GPR:$rk)>;
+  : Pat<(vt (LoadOp (add NonFIBaseAddr:$rj, GPR:$rk))),
+        (Inst NonFIBaseAddr:$rj, GPR:$rk)>;
 
 def : RegRegLdPat<extloadi8, LDX_B, i64>;
 def : RegRegLdPat<sextloadi8, LDX_B, i64>;
@@ -1036,8 +1037,8 @@ def : Pat<(store (i64 GPR:$rd), (AddLike BaseAddr:$rj, simm14_lsl2:$imm14)),
 let Predicates = [IsLA64] in {
 class RegRegStPat<PatFrag StoreOp, LAInst Inst, RegisterClass StTy,
                   ValueType vt>
-  : Pat<(StoreOp (vt StTy:$rd), (add BaseAddr:$rj, GPR:$rk)),
-        (Inst StTy:$rd, BaseAddr:$rj, GPR:$rk)>;
+  : Pat<(StoreOp (vt StTy:$rd), (add NonFIBaseAddr:$rj, GPR:$rk)),
+        (Inst StTy:$rd, NonFIBaseAddr:$rj, GPR:$rk)>;
 
 def : RegRegStPat<truncstorei8, STX_B, GPR, i64>;
 def : RegRegStPat<truncstorei16, STX_H, GPR, i64>;

diff --git a/llvm/lib/Target/LoongArch/LoongArchRegisterInfo.cpp b/llvm/lib/Target/LoongArch/LoongArchRegisterInfo.cpp
@@ -114,6 +114,9 @@ void LoongArchRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
   assert(SPAdj == 0 && "Unexpected non-zero SPAdj value");
 
   MachineInstr &MI = *II;
+  assert(MI.getOperand(FIOperandNum + 1).isImm() &&
+         "Unexpected FI-consuming insn");
+
   MachineBasicBlock &MBB = *MI.getParent();
   MachineFunction &MF = *MI.getParent()->getParent();
   MachineRegisterInfo &MRI = MF.getRegInfo();

diff --git a/llvm/test/CodeGen/LoongArch/ldx-stx-sp-1.ll b/llvm/test/CodeGen/LoongArch/ldx-stx-sp-1.ll
@@ -0,0 +1,68 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc --mtriple=loongarch64 --mattr=+f < %s | FileCheck %s
+
+;; This should not crash the code generator, but the indexed loads/stores
+;; should still be present (the important part is that [f]{ld,st}x shouldn't
+;; take an $sp argument).
+
+define i8 @test_load_i(i64 %i) {
+; CHECK-LABEL: test_load_i:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    addi.d $sp, $sp, -16
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    addi.d $a1, $sp, 8
+; CHECK-NEXT:    ldx.b $a0, $a0, $a1
+; CHECK-NEXT:    addi.d $sp, $sp, 16
+; CHECK-NEXT:    ret
+  %1 = alloca ptr
+  %2 = getelementptr inbounds i8, ptr %1, i64 %i
+  %3 = load i8, ptr %2
+  ret i8 %3
+}
+
+define float @test_load_f(i64 %i) {
+; CHECK-LABEL: test_load_f:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    addi.d $sp, $sp, -16
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    slli.d $a0, $a0, 2
+; CHECK-NEXT:    addi.d $a1, $sp, 8
+; CHECK-NEXT:    fldx.s $fa0, $a0, $a1
+; CHECK-NEXT:    addi.d $sp, $sp, 16
+; CHECK-NEXT:    ret
+  %1 = alloca ptr
+  %2 = getelementptr inbounds float, ptr %1, i64 %i
+  %3 = load float, ptr %2
+  ret float %3
+}
+
+define void @test_store_i(i64 %i, i8 %v) {
+; CHECK-LABEL: test_store_i:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    addi.d $sp, $sp, -16
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    addi.d $a2, $sp, 8
+; CHECK-NEXT:    stx.b $a1, $a0, $a2
+; CHECK-NEXT:    addi.d $sp, $sp, 16
+; CHECK-NEXT:    ret
+  %1 = alloca ptr
+  %2 = getelementptr inbounds i8, ptr %1, i64 %i
+  store i8 %v, ptr %2, align 1
+  ret void
+}
+
+define void @test_store_f(i64 %i, float %v) {
+; CHECK-LABEL: test_store_f:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    addi.d $sp, $sp, -16
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    slli.d $a0, $a0, 2
+; CHECK-NEXT:    addi.d $a1, $sp, 8
+; CHECK-NEXT:    fstx.s $fa0, $a0, $a1
+; CHECK-NEXT:    addi.d $sp, $sp, 16
+; CHECK-NEXT:    ret
+  %1 = alloca ptr
+  %2 = getelementptr inbounds float, ptr %1, i64 %i
+  store float %v, ptr %2, align 4
+  ret void
+}
diff --git a/llvm/test/CodeGen/LoongArch/ldx-stx-sp-2.ll b/llvm/test/CodeGen/LoongArch/ldx-stx-sp-2.ll
@@ -0,0 +1,20 @@
+; RUN: llc --mtriple=loongarch32 < %s
+; RUN: llc --mtriple=loongarch64 < %s
+
+;; This should not crash the code generator.
+
+@.str.2 = external dso_local unnamed_addr constant [69 x i8], align 1
+
+define dso_local void @main() {
+entry:
+  %n0 = alloca [2 x [3 x i32]], align 4
+  %0 = load i32, ptr poison, align 4
+  %idxprom15 = sext i32 %0 to i64
+  %arrayidx16 = getelementptr inbounds [2 x [3 x i32]], ptr %n0, i64 0, i64 %idxprom15
+  %arrayidx17 = getelementptr inbounds [3 x i32], ptr %arrayidx16, i64 0, i64 0
+  %1 = load i32, ptr %arrayidx17, align 4
+  call void (ptr, ...) @printf(ptr noundef @.str.2, i32 noundef signext %1)
+  ret void
+}
+
+declare void @printf(ptr, ...)
diff --git a/llvm/test/CodeGen/LoongArch/ldx-stx-sp-3.ll b/llvm/test/CodeGen/LoongArch/ldx-stx-sp-3.ll
@@ -0,0 +1,23 @@
+; RUN: llc --mtriple=loongarch32 < %s
+; RUN: llc --mtriple=loongarch64 < %s
+
+;; This should not crash the code generator.
+
+define void @_ZN12_GLOBAL__N_111DumpVisitorclIN4llvm16itanium_demangle8FoldExprEEEvPKT_() {
+entry:
+  %ref.tmp6.i.i = alloca [4 x i8], align 1
+  br label %for.cond.i.i
+
+for.cond.i.i:                                     ; preds = %for.body.i.i, %entry
+  %__begin0.0.add.i.i = add nuw nsw i64 poison, 1
+  br label %for.body.i.i
+
+for.body.i.i:                                     ; preds = %for.cond.i.i
+  %__begin0.0.ptr.i.i = getelementptr inbounds i8, ptr %ref.tmp6.i.i, i64 %__begin0.0.add.i.i
+  %0 = load i8, ptr %__begin0.0.ptr.i.i, align 1
+  %tobool18.not.i.i = icmp eq i8 %0, 0
+  br i1 %tobool18.not.i.i, label %for.cond.i.i, label %exit
+
+exit: ; preds = %for.body.i.i
+  unreachable
+}