Add @earlyclobber constraints to the writeback register of all ARM store instructions.

The ARMARM specifies these instructions as unpredictable when storing the
writeback register. This shouldn't affect code generation much since storing a
pointer to itself is quite rare.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129409 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 24 insertions, 12 deletions

diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index d10f1f1d58..eb8f4aad4c 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -1802,41 +1802,47 @@ def STRD : AI3str<0b1111, (outs), (ins GPR:$Rt, GPR:$src2, addrmode3:$addr),
 def STR_PRE  : AI2stridx<0, 1, (outs GPR:$Rn_wb),
                      (ins GPR:$Rt, GPR:$Rn, am2offset:$offset),
                      IndexModePre, StFrm, IIC_iStore_ru,
-                     "str", "\t$Rt, [$Rn, $offset]!", "$Rn = $Rn_wb",
+                     "str", "\t$Rt, [$Rn, $offset]!",
+                     "$Rn = $Rn_wb,@earlyclobber $Rn_wb",
                      [(set GPR:$Rn_wb,
                       (pre_store GPR:$Rt, GPR:$Rn, am2offset:$offset))]>;
 
 def STR_POST : AI2stridx<0, 0, (outs GPR:$Rn_wb),
                      (ins GPR:$Rt, GPR:$Rn, am2offset:$offset),
                      IndexModePost, StFrm, IIC_iStore_ru,
-                     "str", "\t$Rt, [$Rn], $offset", "$Rn = $Rn_wb",
+                     "str", "\t$Rt, [$Rn], $offset",
+                     "$Rn = $Rn_wb,@earlyclobber $Rn_wb",
                      [(set GPR:$Rn_wb,
                       (post_store GPR:$Rt, GPR:$Rn, am2offset:$offset))]>;
 
 def STRB_PRE : AI2stridx<1, 1, (outs GPR:$Rn_wb),
                      (ins GPR:$Rt, GPR:$Rn, am2offset:$offset),
                      IndexModePre, StFrm, IIC_iStore_bh_ru,
-                     "strb", "\t$Rt, [$Rn, $offset]!", "$Rn = $Rn_wb",
+                     "strb", "\t$Rt, [$Rn, $offset]!",
+                     "$Rn = $Rn_wb,@earlyclobber $Rn_wb",
                      [(set GPR:$Rn_wb, (pre_truncsti8 GPR:$Rt,
                                         GPR:$Rn, am2offset:$offset))]>;
 def STRB_POST: AI2stridx<1, 0, (outs GPR:$Rn_wb),
                      (ins GPR:$Rt, GPR:$Rn, am2offset:$offset),
                      IndexModePost, StFrm, IIC_iStore_bh_ru,
-                     "strb", "\t$Rt, [$Rn], $offset", "$Rn = $Rn_wb",
+                     "strb", "\t$Rt, [$Rn], $offset",
+                     "$Rn = $Rn_wb,@earlyclobber $Rn_wb",
                      [(set GPR:$Rn_wb, (post_truncsti8 GPR:$Rt,
                                         GPR:$Rn, am2offset:$offset))]>;
 
 def STRH_PRE : AI3stridx<0b1011, 0, 1, (outs GPR:$Rn_wb),
                      (ins GPR:$Rt, GPR:$Rn, am3offset:$offset),
                      IndexModePre, StMiscFrm, IIC_iStore_ru,
-                     "strh", "\t$Rt, [$Rn, $offset]!", "$Rn = $Rn_wb",
+                     "strh", "\t$Rt, [$Rn, $offset]!",
+                     "$Rn = $Rn_wb,@earlyclobber $Rn_wb",
                      [(set GPR:$Rn_wb,
                       (pre_truncsti16 GPR:$Rt, GPR:$Rn, am3offset:$offset))]>;
 
 def STRH_POST: AI3stridx<0b1011, 0, 0, (outs GPR:$Rn_wb),
                      (ins GPR:$Rt, GPR:$Rn, am3offset:$offset),
                      IndexModePost, StMiscFrm, IIC_iStore_bh_ru,
-                     "strh", "\t$Rt, [$Rn], $offset", "$Rn = $Rn_wb",
+                     "strh", "\t$Rt, [$Rn], $offset",
+                     "$Rn = $Rn_wb,@earlyclobber $Rn_wb",
                      [(set GPR:$Rn_wb, (post_truncsti16 GPR:$Rt,
                                         GPR:$Rn, am3offset:$offset))]>;
 
diff --git a/lib/Target/ARM/ARMInstrThumb2.td b/lib/Target/ARM/ARMInstrThumb2.td
index a560a80568..93d841ff87 100644
--- a/lib/Target/ARM/ARMInstrThumb2.td
+++ b/lib/Target/ARM/ARMInstrThumb2.td
@@ -1423,42 +1423,48 @@ def t2STRDi8 : T2Ii8s4<1, 0, 0, (outs),
 def t2STR_PRE  : T2Iidxldst<0, 0b10, 0, 1, (outs GPR:$base_wb),
                             (ins GPR:$Rt, GPR:$Rn, t2am_imm8_offset:$addr),
                             AddrModeT2_i8, IndexModePre, IIC_iStore_iu,
-                         "str", "\t$Rt, [$Rn, $addr]!", "$Rn = $base_wb",
+                         "str", "\t$Rt, [$Rn, $addr]!",
+                         "$Rn = $base_wb,@earlyclobber $base_wb",
              [(set GPR:$base_wb,
                    (pre_store GPR:$Rt, GPR:$Rn, t2am_imm8_offset:$addr))]>;
 
 def t2STR_POST : T2Iidxldst<0, 0b10, 0, 0, (outs GPR:$base_wb),
                             (ins GPR:$Rt, GPR:$Rn, t2am_imm8_offset:$addr),
                             AddrModeT2_i8, IndexModePost, IIC_iStore_iu,
-                          "str", "\t$Rt, [$Rn], $addr", "$Rn = $base_wb",
+                          "str", "\t$Rt, [$Rn], $addr",
+                          "$Rn = $base_wb,@earlyclobber $base_wb",
              [(set GPR:$base_wb,
                   (post_store GPR:$Rt, GPR:$Rn, t2am_imm8_offset:$addr))]>;
 
 def t2STRH_PRE  : T2Iidxldst<0, 0b01, 0, 1, (outs GPR:$base_wb),
                             (ins GPR:$Rt, GPR:$Rn, t2am_imm8_offset:$addr),
                             AddrModeT2_i8, IndexModePre, IIC_iStore_iu,
-                        "strh", "\t$Rt, [$Rn, $addr]!", "$Rn = $base_wb",
+                        "strh", "\t$Rt, [$Rn, $addr]!",
+                        "$Rn = $base_wb,@earlyclobber $base_wb",
         [(set GPR:$base_wb,
               (pre_truncsti16 GPR:$Rt, GPR:$Rn, t2am_imm8_offset:$addr))]>;
 
 def t2STRH_POST : T2Iidxldst<0, 0b01, 0, 0, (outs GPR:$base_wb),
                             (ins GPR:$Rt, GPR:$Rn, t2am_imm8_offset:$addr),
                             AddrModeT2_i8, IndexModePost, IIC_iStore_bh_iu,
-                         "strh", "\t$Rt, [$Rn], $addr", "$Rn = $base_wb",
+                         "strh", "\t$Rt, [$Rn], $addr",
+                         "$Rn = $base_wb,@earlyclobber $base_wb",
        [(set GPR:$base_wb,
              (post_truncsti16 GPR:$Rt, GPR:$Rn, t2am_imm8_offset:$addr))]>;
 
 def t2STRB_PRE  : T2Iidxldst<0, 0b00, 0, 1, (outs GPR:$base_wb),
                             (ins GPR:$Rt, GPR:$Rn, t2am_imm8_offset:$addr),
                             AddrModeT2_i8, IndexModePre, IIC_iStore_bh_iu,
-                        "strb", "\t$Rt, [$Rn, $addr]!", "$Rn = $base_wb",
+                        "strb", "\t$Rt, [$Rn, $addr]!",
+                        "$Rn = $base_wb,@earlyclobber $base_wb",
          [(set GPR:$base_wb,
                (pre_truncsti8 GPR:$Rt, GPR:$Rn, t2am_imm8_offset:$addr))]>;
 
 def t2STRB_POST : T2Iidxldst<0, 0b00, 0, 0, (outs GPR:$base_wb),
                             (ins GPR:$Rt, GPR:$Rn, t2am_imm8_offset:$addr),
                             AddrModeT2_i8, IndexModePost, IIC_iStore_bh_iu,
-                         "strb", "\t$Rt, [$Rn], $addr", "$Rn = $base_wb",
+                         "strb", "\t$Rt, [$Rn], $addr",
+                         "$Rn = $base_wb,@earlyclobber $base_wb",
         [(set GPR:$base_wb,
               (post_truncsti8 GPR:$Rt, GPR:$Rn, t2am_imm8_offset:$addr))]>;