[AArch64] Fix registerAllocator assigns same register for base and wback in

pre/post-index load and store.

Patch by Steven Wu <stevenwu@apple.com>

llvm-svn: 215390

2 files changed, 18 insertions, 7 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64InstrFormats.td b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
index 3f764239290..6a1bab52ab8 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrFormats.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
@@ -2998,7 +2998,7 @@ class LoadPreIdx<bits<2> sz, bit V, bits<2> opc, RegisterClass regtype,
     : BaseLoadStorePreIdx<sz, V, opc,
                      (outs GPR64sp:$wback, regtype:$Rt),
                      (ins GPR64sp:$Rn, simm9:$offset), asm,
-                     "$Rn = $wback", []>,
+                     "$Rn = $wback,@earlyclobber $wback", []>,
       Sched<[WriteLD, WriteAdr]>;
 
 let mayStore = 1, mayLoad = 0 in
@@ -3007,7 +3007,7 @@ class StorePreIdx<bits<2> sz, bit V, bits<2> opc, RegisterClass regtype,
     : BaseLoadStorePreIdx<sz, V, opc,
                       (outs GPR64sp:$wback),
                       (ins regtype:$Rt, GPR64sp:$Rn, simm9:$offset),
-                      asm, "$Rn = $wback",
+                      asm, "$Rn = $wback,@earlyclobber $wback",
       [(set GPR64sp:$wback,
             (storeop (Ty regtype:$Rt), GPR64sp:$Rn, simm9:$offset))]>,
       Sched<[WriteAdr, WriteST]>;
@@ -3017,7 +3017,6 @@ class StorePreIdx<bits<2> sz, bit V, bits<2> opc, RegisterClass regtype,
 // Load/store post-indexed
 //---
 
-// (pre-index) load/stores.
 class BaseLoadStorePostIdx<bits<2> sz, bit V, bits<2> opc, dag oops, dag iops,
                           string asm, string cstr, list<dag> pat>
     : I<oops, iops, asm, "\t$Rt, [$Rn], $offset", cstr, pat> {
@@ -3045,7 +3044,7 @@ class LoadPostIdx<bits<2> sz, bit V, bits<2> opc, RegisterClass regtype,
     : BaseLoadStorePostIdx<sz, V, opc,
                       (outs GPR64sp:$wback, regtype:$Rt),
                       (ins GPR64sp:$Rn, simm9:$offset),
-                      asm, "$Rn = $wback", []>,
+                      asm, "$Rn = $wback,@earlyclobber $wback", []>,
       Sched<[WriteLD, WriteI]>;
 
 let mayStore = 1, mayLoad = 0 in
@@ -3054,7 +3053,7 @@ class StorePostIdx<bits<2> sz, bit V, bits<2> opc, RegisterClass regtype,
     : BaseLoadStorePostIdx<sz, V, opc,
                       (outs GPR64sp:$wback),
                       (ins regtype:$Rt, GPR64sp:$Rn, simm9:$offset),
-                       asm, "$Rn = $wback",
+                       asm, "$Rn = $wback,@earlyclobber $wback",
       [(set GPR64sp:$wback,
             (storeop (Ty regtype:$Rt), GPR64sp:$Rn, simm9:$offset))]>,
     Sched<[WriteAdr, WriteST, ReadAdrBase]>;
@@ -3118,7 +3117,7 @@ multiclass StorePairOffset<bits<2> opc, bit V, RegisterClass regtype,
 // (pre-indexed)
 class BaseLoadStorePairPreIdx<bits<2> opc, bit V, bit L, dag oops, dag iops,
                               string asm>
-    : I<oops, iops, asm, "\t$Rt, $Rt2, [$Rn, $offset]!", "$Rn = $wback", []> {
+    : I<oops, iops, asm, "\t$Rt, $Rt2, [$Rn, $offset]!", "$Rn = $wback,@earlyclobber $wback", []> {
   bits<5> Rt;
   bits<5> Rt2;
   bits<5> Rn;
@@ -3159,7 +3158,7 @@ class StorePairPreIdx<bits<2> opc, bit V, RegisterClass regtype,
 
 class BaseLoadStorePairPostIdx<bits<2> opc, bit V, bit L, dag oops, dag iops,
                               string asm>
-    : I<oops, iops, asm, "\t$Rt, $Rt2, [$Rn], $offset", "$Rn = $wback", []> {
+    : I<oops, iops, asm, "\t$Rt, $Rt2, [$Rn], $offset", "$Rn = $wback,@earlyclobber $wback", []> {
   bits<5> Rt;
   bits<5> Rt2;
   bits<5> Rn;
diff --git a/llvm/test/CodeGen/AArch64/arm64-indexed-memory.ll b/llvm/test/CodeGen/AArch64/arm64-indexed-memory.ll
index e501c6e403b..a8620f428da 100644
--- a/llvm/test/CodeGen/AArch64/arm64-indexed-memory.ll
+++ b/llvm/test/CodeGen/AArch64/arm64-indexed-memory.ll
@@ -349,3 +349,15 @@ define i8* @preidx8sext64(i8* %src, i64* %out) {
   store i64 %ext, i64* %out, align 4
   ret i8* %ptr
 }
+
+; This test checks if illegal post-index is generated
+
+define i64* @postidx_clobber(i64* %addr) nounwind noinline ssp {
+; CHECK-LABEL: postidx_clobber:
+; CHECK-NOT: str     x0, [x0], #8
+; ret
+ %paddr = bitcast i64* %addr to i64**
+ store i64* %addr, i64** %paddr
+ %newaddr = getelementptr i64* %addr, i32 1
+ ret i64* %newaddr
+}