[RISCV] Change more undef passthrus to $noreg in vector tests. NFC

Author: lukel97

llvm/test/CodeGen/RISCV/rvv/addi-scalable-offset.mir

@@ -57,8 +57,7 @@ body: |
     ; CHECK-NEXT: PseudoRET
     %1:gprnox0 = COPY $x11
     %0:gpr = COPY $x10
-    %pt:vr = IMPLICIT_DEF
-    %2:vr = PseudoVLE64_V_M1 %pt, %0, %1, 6, 0 :: (load unknown-size from %ir.pa, align 8)
+    %2:vr = PseudoVLE64_V_M1 undef $noreg, %0, %1, 6, 0 :: (load unknown-size from %ir.pa, align 8)
     %3:gpr = ADDI %stack.2, 0
     VS1R_V killed %2:vr, %3:gpr
     PseudoRET

llvm/test/CodeGen/RISCV/rvv/copyprop.mir

@@ -43,16 +43,12 @@ body:             |
     %2:gpr = COPY $x11
     %1:gpr = COPY $x10
     %3:vr = COPY $v8
-    %pt5:vr = IMPLICIT_DEF
-    %17:vr = PseudoVSLL_VI_M1 %pt5, %3, 5, 1, 6 /* e64 */, 0
+    %17:vr = PseudoVSLL_VI_M1 undef $noreg, %3, 5, 1, 6 /* e64 */, 0
     %22:vr = PseudoVMSNE_VI_M1 %3, 0, 1, 6 /* e64 */
     $v0 = COPY %22
-    %26:vrnov0 = IMPLICIT_DEF
-    %25:vrnov0 = PseudoVMERGE_VIM_M1 %26, %17, -1, $v0, 1, 6 /* e64 */
-    %pt8:vr = IMPLICIT_DEF
+    %25:vrnov0 = PseudoVMERGE_VIM_M1 undef $noreg, %17, -1, $v0, 1, 6 /* e64 */
     %29:vr = PseudoVC_V_X_SE_M1 3, 31, %2, 1, 6 /* e64 */, implicit-def dead $vcix_state, implicit $vcix_state
-    %pt9:vr = IMPLICIT_DEF
-    %30:vr = PseudoVMV_V_I_M1 %pt9, 0, 1, 6 /* e64 */, 0
+    %30:vr = PseudoVMV_V_I_M1 undef $noreg, 0, 1, 6 /* e64 */, 0
     BGEU %1, $x0, %bb.2
 
   bb.1.entry:

llvm/test/CodeGen/RISCV/rvv/mask-reg-alloc.mir

@@ -27,13 +27,10 @@ body:             |
     %2:vr = COPY $v2
     %3:vr = COPY $v3
     %4:vmv0 = COPY %0
-    %pt1:vrnov0 = IMPLICIT_DEF
-    %5:vrnov0 = PseudoVMERGE_VIM_M1 %pt1, killed %2, 1, %4, 1, 3
+    %5:vrnov0 = PseudoVMERGE_VIM_M1 undef $noreg, killed %2, 1, %4, 1, 3
     %6:vmv0 = COPY %1
-    %pt2:vrnov0 = IMPLICIT_DEF
-    %7:vrnov0 = PseudoVMERGE_VIM_M1 %pt2, killed %3, 1, %6, 1, 3
-    %pt:vr = IMPLICIT_DEF
-    %8:vr = PseudoVADD_VV_M1 %pt, killed %5, killed %7, 1, 3, 0
+    %7:vrnov0 = PseudoVMERGE_VIM_M1 undef $noreg, killed %3, 1, %6, 1, 3
+    %8:vr = PseudoVADD_VV_M1 undef $noreg, killed %5, killed %7, 1, 3, 0
     $v0 = COPY %8
     PseudoRET implicit $v0
 ...

llvm/test/CodeGen/RISCV/rvv/vxrm.mir

@@ -24,7 +24,6 @@ body:     |
     %0:vr = COPY $v8
     %1:vr = COPY $v9
     %2:gprnox0 = COPY $x10
-    %pt:vr = IMPLICIT_DEF
-    renamable $v8 = PseudoVAADD_VV_MF8 %pt, %0, %1, 0, %2, 3 /* e8 */, 0
+    renamable $v8 = PseudoVAADD_VV_MF8 undef $noreg, %0, %1, 0, %2, 3 /* e8 */, 0
     PseudoRET implicit $v8
 ...