From 52338af5695e48bfd74fdb8e253b32ba82b016f5 Mon Sep 17 00:00:00 2001
From: Nick Desaulniers <ndesaulniers@google.com>
Date: Thu, 1 Apr 2021 10:32:28 -0700
Subject: [PATCH] [MC][ARM] add .w suffixes for RSB/RSBS T1

See also:
F5.1.167 RSB, RSBS (register) T1 shift or rotate by value variant
of the Arm ARM.

Link: https://github.com/ClangBuiltLinux/linux/issues/1309

Reviewed By: DavidSpickett

Differential Revision: https://reviews.llvm.org/D99542
---
 llvm/lib/Target/ARM/ARMInstrThumb2.td        | 11 +++++++++--
 llvm/test/MC/ARM/basic-thumb2-instructions.s | 12 ++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Target/ARM/ARMInstrThumb2.td b/llvm/lib/Target/ARM/ARMInstrThumb2.td
index bc772f35b5b3..794b666a568b 100644
--- a/llvm/lib/Target/ARM/ARMInstrThumb2.td
+++ b/llvm/lib/Target/ARM/ARMInstrThumb2.td
@@ -5064,8 +5064,8 @@ def : t2InstAlias<"rev16${p} $Rd, $Rm", (t2REV16 rGPR:$Rd, rGPR:$Rm, pred:$p)>;
 def : t2InstAlias<"revsh${p} $Rd, $Rm", (t2REVSH rGPR:$Rd, rGPR:$Rm, pred:$p)>;
 
 
-// Alias for RSB without the ".w" optional width specifier, and with optional
-// implied destination register.
+// Alias for RSB with and without the ".w" optional width specifier, with and
+// without explicit destination register.
 def : t2InstAlias<"rsb${s}${p} $Rd, $Rn, $imm",
            (t2RSBri rGPR:$Rd, rGPR:$Rn, t2_so_imm:$imm, pred:$p, cc_out:$s)>;
 def : t2InstAlias<"rsb${s}${p} $Rdn, $imm",
@@ -5075,6 +5075,13 @@ def : t2InstAlias<"rsb${s}${p} $Rdn, $Rm",
 def : t2InstAlias<"rsb${s}${p} $Rdn, $ShiftedRm",
            (t2RSBrs rGPR:$Rdn, rGPR:$Rdn, t2_so_reg:$ShiftedRm, pred:$p,
                     cc_out:$s)>;
+def : t2InstAlias<"rsb${s}${p}.w $Rdn, $Rm",
+           (t2RSBrr rGPR:$Rdn, rGPR:$Rdn, rGPR:$Rm, pred:$p, cc_out:$s)>;
+def : t2InstAlias<"rsb${s}${p}.w $Rd, $Rn, $Rm",
+           (t2RSBrr rGPR:$Rd, rGPR:$Rn, rGPR:$Rm, pred:$p, cc_out:$s)>;
+def : t2InstAlias<"rsb${s}${p}.w $Rd, $Rn, $ShiftedRm",
+           (t2RSBrs rGPR:$Rd, rGPR:$Rn, t2_so_reg:$ShiftedRm, pred:$p,
+                    cc_out:$s)>;
 
 // SSAT/USAT optional shift operand.
 def : t2InstAlias<"ssat${p} $Rd, $sat_imm, $Rn",
diff --git a/llvm/test/MC/ARM/basic-thumb2-instructions.s b/llvm/test/MC/ARM/basic-thumb2-instructions.s
index 636067a6f37b..b8afd2917fd0 100644
--- a/llvm/test/MC/ARM/basic-thumb2-instructions.s
+++ b/llvm/test/MC/ARM/basic-thumb2-instructions.s
@@ -2278,14 +2278,26 @@ adds sp, #-4096
 @ RSB (register)
 @------------------------------------------------------------------------------
         rsb r4, r8
+        rsb.w r4, r8
         rsb r4, r9, r8
+        rsb.w r4, r9, r8
         rsb r1, r4, r8, asr #3
+        rsb.w r1, r4, r8, asr #3
         rsbs r2, r1, r7, lsl #1
+        rsbs.w r2, r1, r7, lsl #1
+        rsbs r0, r1, r2
+        rsbs.w r0, r1, r2
 
 @ CHECK: rsb	r4, r4, r8              @ encoding: [0xc4,0xeb,0x08,0x04]
+@ CHECK: rsb	r4, r4, r8              @ encoding: [0xc4,0xeb,0x08,0x04]
+@ CHECK: rsb	r4, r9, r8              @ encoding: [0xc9,0xeb,0x08,0x04]
 @ CHECK: rsb	r4, r9, r8              @ encoding: [0xc9,0xeb,0x08,0x04]
 @ CHECK: rsb	r1, r4, r8, asr #3      @ encoding: [0xc4,0xeb,0xe8,0x01]
+@ CHECK: rsb	r1, r4, r8, asr #3      @ encoding: [0xc4,0xeb,0xe8,0x01]
 @ CHECK: rsbs	r2, r1, r7, lsl #1      @ encoding: [0xd1,0xeb,0x47,0x02]
+@ CHECK: rsbs	r2, r1, r7, lsl #1      @ encoding: [0xd1,0xeb,0x47,0x02]
+@ CHECK: rsbs	r0, r1, r2              @ encoding: [0xd1,0xeb,0x02,0x00]
+@ CHECK: rsbs	r0, r1, r2              @ encoding: [0xd1,0xeb,0x02,0x00]
 
 
 @------------------------------------------------------------------------------