From: Jim Grosbach <grosbach@apple.com>
Date: Wed, 14 Dec 2011 17:30:24 +0000 (+0000)
Subject: ARM/Thumb2 'cmp rn, #imm' alias to cmn.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=8d11c6349f9bf276534907245946518042c1bb60;p=oota-llvm.git

ARM/Thumb2 'cmp rn, #imm' alias to cmn.

When 'cmp rn #imm' doesn't match due to the immediate not being representable,
but 'cmn rn, #-imm' does match, use the latter in place of the former, as
it's equivalent.

rdar://10552389

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146567 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index 74167d0e499..3dc6284e693 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -5089,6 +5089,11 @@ def : ARMInstAlias<"add${s}${p} $Rd, $Rn, $imm",
                  (SUBri GPR:$Rd, GPR:$Rn, so_imm_neg:$imm, pred:$p, cc_out:$s)>;
 def : ARMInstAlias<"add${s}${p} $Rd, $imm",
                  (SUBri GPR:$Rd, GPR:$Rd, so_imm_neg:$imm, pred:$p, cc_out:$s)>;
+// Same for CMP <--> CMN via t2_so_imm_neg
+def : ARMInstAlias<"cmp${p} $Rd, $imm",
+                   (CMNzri rGPR:$Rd, t2_so_imm_neg:$imm, pred:$p)>;
+def : ARMInstAlias<"cmn${p} $Rd, $imm",
+                   (CMPri rGPR:$Rd, t2_so_imm_neg:$imm, pred:$p)>;
 
 // The shifter forms of the MOV instruction are aliased to the ASR, LSL,
 // LSR, ROR, and RRX instructions.
diff --git a/lib/Target/ARM/ARMInstrThumb2.td b/lib/Target/ARM/ARMInstrThumb2.td
index c8ab59fc6f1..0bce0735a27 100644
--- a/lib/Target/ARM/ARMInstrThumb2.td
+++ b/lib/Target/ARM/ARMInstrThumb2.td
@@ -4110,13 +4110,18 @@ def : t2InstAlias<"and${s}${p} $Rd, $Rn, $imm",
 def : t2InstAlias<"and${s}${p} $Rdn, $imm",
                   (t2BICri rGPR:$Rdn, rGPR:$Rdn, so_imm_not:$imm,
                            pred:$p, cc_out:$s)>;
-// Likewise, "add Rd, so_imm_neg" -> sub
+// Likewise, "add Rd, t2_so_imm_neg" -> sub
 def : t2InstAlias<"add${s}${p} $Rd, $Rn, $imm",
                   (t2SUBri GPRnopc:$Rd, GPRnopc:$Rn, t2_so_imm_neg:$imm,
                            pred:$p, cc_out:$s)>;
 def : t2InstAlias<"add${s}${p} $Rd, $imm",
                   (t2SUBri GPRnopc:$Rd, GPRnopc:$Rd, t2_so_imm_neg:$imm,
                            pred:$p, cc_out:$s)>;
+// Same for CMP <--> CMN via t2_so_imm_neg
+def : t2InstAlias<"cmp${p} $Rd, $imm",
+                  (t2CMNzri rGPR:$Rd, t2_so_imm_neg:$imm, pred:$p)>;
+def : t2InstAlias<"cmn${p} $Rd, $imm",
+                  (t2CMPri rGPR:$Rd, t2_so_imm_neg:$imm, pred:$p)>;
 
 
 // Wide 'mul' encoding can be specified with only two operands.
diff --git a/test/MC/ARM/basic-arm-instructions.s b/test/MC/ARM/basic-arm-instructions.s
index a45c30300fb..080bc6f2cb1 100644
--- a/test/MC/ARM/basic-arm-instructions.s
+++ b/test/MC/ARM/basic-arm-instructions.s
@@ -493,6 +493,7 @@ Lforward:
         cmp r7, r8, asr r2
         cmp r7, r8, ror r2
         cmp r1, r6, rrx
+        cmp r0, #-2
 
 @ CHECK: cmp	r1, #15                 @ encoding: [0x0f,0x00,0x51,0xe3]
 @ CHECK: cmp	r1, r6                  @ encoding: [0x06,0x00,0x51,0xe1]
@@ -506,6 +507,7 @@ Lforward:
 @ CHECK: cmp	r7, r8, asr r2          @ encoding: [0x58,0x02,0x57,0xe1]
 @ CHECK: cmp	r7, r8, ror r2          @ encoding: [0x78,0x02,0x57,0xe1]
 @ CHECK: cmp	r1, r6, rrx             @ encoding: [0x66,0x00,0x51,0xe1]
+@ CHECK: cmn	r0, #2                  @ encoding: [0x02,0x00,0x70,0xe3]
 
 
 @------------------------------------------------------------------------------
diff --git a/test/MC/ARM/basic-thumb2-instructions.s b/test/MC/ARM/basic-thumb2-instructions.s
index 028e17bdc9a..be640f00692 100644
--- a/test/MC/ARM/basic-thumb2-instructions.s
+++ b/test/MC/ARM/basic-thumb2-instructions.s
@@ -368,6 +368,7 @@ _func:
         cmp sp, r6, lsr #1
         cmp r2, r5, asr #24
         cmp r1, r4, ror #15
+        cmp r0, #-2
 
 @ CHECK: cmp.w	r5, #65280              @ encoding: [0xb5,0xf5,0x7f,0x4f]
 @ CHECK: cmp.w	r4, r12                 @ encoding: [0xb4,0xeb,0x0c,0x0f]
@@ -376,7 +377,7 @@ _func:
 @ CHECK: cmp.w	sp, r6, lsr #1          @ encoding: [0xbd,0xeb,0x56,0x0f]
 @ CHECK: cmp.w	r2, r5, asr #24         @ encoding: [0xb2,0xeb,0x25,0x6f]
 @ CHECK: cmp.w	r1, r4, ror #15         @ encoding: [0xb1,0xeb,0xf4,0x3f]
-
+@ CHECK: cmn.w	r0, #2                  @ encoding: [0x10,0xf1,0x02,0x0f]
 
 @------------------------------------------------------------------------------
 @ DBG