s390x: Fix more regalloc checker errors (#5121)

For VecInsertLane[Undef] and VecExtractLane, if lane_reg is zero_reg(), the instruction does not actually use any register value. Fixes #5090
bytecodealliance · Oct 25, 2022 · b61e678 · b61e678
1 parent 39b3b1d
commit b61e678
Showing 1 changed file with 9 additions and 3 deletions.
diff --git a/cranelift/codegen/src/isa/s390x/inst/mod.rs b/cranelift/codegen/src/isa/s390x/inst/mod.rs
@@ -974,21 +974,27 @@ fn s390x_get_operands<F: Fn(VReg) -> VReg>(inst: &Inst, collector: &mut OperandC
             collector.reg_reuse_def(rd, 1);
             collector.reg_use(ri);
             collector.reg_use(rn);
-            collector.reg_use(lane_reg);
+            if lane_reg != zero_reg() {
+                collector.reg_use(lane_reg);
+            }
         }
         &Inst::VecInsertLaneUndef {
             rd, rn, lane_reg, ..
         } => {
             collector.reg_def(rd);
             collector.reg_use(rn);
-            collector.reg_use(lane_reg);
+            if lane_reg != zero_reg() {
+                collector.reg_use(lane_reg);
+            }
         }
         &Inst::VecExtractLane {
             rd, rn, lane_reg, ..
         } => {
             collector.reg_def(rd);
             collector.reg_use(rn);
-            collector.reg_use(lane_reg);
+            if lane_reg != zero_reg() {
+                collector.reg_use(lane_reg);
+            }
         }
         &Inst::VecInsertLaneImm { rd, ri, .. } => {
             collector.reg_reuse_def(rd, 1);