x86_64: fix @bitCast when the operand dies

ziglang · May 19, 2023 · 47405b1 · 47405b1
1 parent 79bdd2b
commit 47405b1
Showing 1 changed file with 12 additions and 8 deletions.
diff --git a/src/arch/x86_64/CodeGen.zig b/src/arch/x86_64/CodeGen.zig
@@ -10154,18 +10154,22 @@ fn airBitCast(self: *Self, inst: Air.Inst.Index) !void {
  const dst_rc = regClassForType(dst_ty);
  const src_rc = regClassForType(src_ty);
  const src_mcv = try self.resolveInst(ty_op.operand);
- if (dst_rc.supersetOf(src_rc) and self.reuseOperand(inst, ty_op.operand, 0, src_mcv))
- break :result src_mcv;
 
  const src_lock = if (src_mcv.getReg()) |reg| self.register_manager.lockReg(reg) else null;
  defer if (src_lock) |lock| self.register_manager.unlockReg(lock);
 
- const dst_mcv = try self.allocRegOrMem(inst, true);
- try self.genCopy(
- if (!dst_mcv.isMemory() or src_mcv.isMemory()) dst_ty else src_ty,
- dst_mcv,
- src_mcv,
- );
+ const dst_mcv = if (dst_rc.supersetOf(src_rc) and
+ self.reuseOperand(inst, ty_op.operand, 0, src_mcv))
+ src_mcv
+ else dst: {
+ const dst_mcv = try self.allocRegOrMem(inst, true);
+ try self.genCopy(
+ if (!dst_mcv.isMemory() or src_mcv.isMemory()) dst_ty else src_ty,
+ dst_mcv,
+ src_mcv,
+ );
+ break :dst dst_mcv;
+ };
 
  const dst_signedness =
  if (dst_ty.isAbiInt()) dst_ty.intInfo(self.target.*).signedness else .unsigned;