[ARM] Support ldr.w in pseudo instruction ldr rd,=immediate

The changes made in r269352, r269353 and r269354 to support the 
transformation of the ldr rd,=immediate to mov introduced a regression
from 3.8 (ldr.w rd, =immediate) not supported.

This change puts support back in for ldr.w by means of a t2InstAlias for
the .w form. The .w is ignored in ARM state and propagated to the ldr in
Thumb2.

llvm-svn: 281319

3 files changed, 78 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMInstrThumb2.td b/llvm/lib/Target/ARM/ARMInstrThumb2.td
index 7d4f27d38aa..9a2dee9048b 100644
--- a/llvm/lib/Target/ARM/ARMInstrThumb2.td
+++ b/llvm/lib/Target/ARM/ARMInstrThumb2.td
@@ -4657,6 +4657,10 @@ def : t2InstAlias<"add${p} $Rd, pc, $imm",
 def t2LDRConstPool
   : t2AsmPseudo<"ldr${p} $Rt, $immediate",
                 (ins GPRnopc:$Rt, const_pool_asm_imm:$immediate, pred:$p)>;
+// Version w/ the .w suffix.
+def : t2InstAlias<"ldr${p}.w $Rt, $immediate",
+                  (t2LDRConstPool GPRnopc:$Rt,
+                  const_pool_asm_imm:$immediate, pred:$p)>;
 
 // PLD/PLDW/PLI with alternate literal form.
 def : t2InstAlias<"pld${p} $addr",
diff --git a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index 78e033f69dd..2b6fda00dc9 100644
--- a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -7103,6 +7103,9 @@ bool ARMAsmParser::processInstruction(MCInst &Inst,
     else if (Inst.getOpcode() == ARM::t2LDRConstPool)
       TmpInst.setOpcode(ARM::t2LDRpci);
     const ARMOperand &PoolOperand =
+      (static_cast<ARMOperand &>(*Operands[2]).isToken() &&
+       static_cast<ARMOperand &>(*Operands[2]).getToken() == ".w") ?
+      static_cast<ARMOperand &>(*Operands[4]) :
       static_cast<ARMOperand &>(*Operands[3]);
     const MCExpr *SubExprVal = PoolOperand.getConstantPoolImm();
     // If SubExprVal is a constant we may be able to use a MOV
diff --git a/llvm/test/MC/ARM/ldr-pseudo-wide.s b/llvm/test/MC/ARM/ldr-pseudo-wide.s
new file mode 100644
index 00000000000..ae1799f706a
--- /dev/null
+++ b/llvm/test/MC/ARM/ldr-pseudo-wide.s
@@ -0,0 +1,71 @@
+@ Test case for PR30352
+@ Check that ldr.w is:
+@ accepted and ignored for ARM
+@ accepted and propagated for Thumb2
+@ rejected as needing Thumb2 for Thumb
+
+@RUN: llvm-mc -triple armv5-unknown-linux-gnueabi %s | FileCheck --check-prefix=CHECK-ARM --check-prefix=CHECK %s
+@RUN: llvm-mc -triple   armv7-base-apple-darwin %s | FileCheck --check-prefix=CHECK-DARWIN-ARM --check-prefix=CHECK-DARWIN %s
+@RUN: llvm-mc -triple thumbv7-unknown-linux-gnueabi %s | FileCheck --check-prefix=CHECK-THUMB2 --check-prefix=CHECK %s
+@RUN: llvm-mc -triple thumbv7-base-apple-darwin %s | FileCheck --check-prefix=CHECK-DARWIN-THUMB2 --check-prefix=CHECK-DARWIN %s
+@RUN: not llvm-mc -triple thumbv6-unknown-linux-gnueabi %s 2>&1 | FileCheck --check-prefix=CHECK-THUMB %s
+@RUN: not llvm-mc -triple thumbv6-base-apple-darwin %s 2>&1 | FileCheck --check-prefix=CHECK-THUMB %s
+@ CHECK-LABEL: f1:
+f1:
+  ldr r0, =0x10002
+@ CHECK-ARM: ldr r0, .Ltmp[[TMP0:[0-9]+]]
+@ CHECK-DARWIN-ARM: ldr r0, Ltmp0
+@ CHECK-THUMB2: ldr r0, .Ltmp[[TMP0:[0-9]+]]
+@ CHECK-DARWIN-THUMB2: ldr r0, Ltmp0
+
+  ldr.w r0, =0x10002
+@ CHECK-ARM: ldr r0, .Ltmp[[TMP1:[0-9]+]]
+@ CHECK-DARWIN-ARM: ldr r0, Ltmp1
+@ CHECK-THUMB2: ldr.w r0, .Ltmp[[TMP1:[0-9]+]]
+@ CHECK-DARWIN-THUMB2: ldr.w r0, Ltmp1
+@ CHECK-THUMB: error: instruction requires: thumb2
+@ CHECK-THUMB-NEXT:  ldr.w r0, =0x10002
+
+@ CHECK-LABEL: f2:
+f2:
+  ldr r0, =foo
+@ CHECK-ARM: ldr r0, .Ltmp[[TMP2:[0-9]+]]
+@ CHECK-DARWIN-ARM: ldr r0, Ltmp2
+@ CHECK-THUMB2: ldr r0, .Ltmp[[TMP2:[0-9]+]]
+@ CHECK-DARWIN-THUMB2: ldr r0, Ltmp2
+
+  ldr.w r0, =foo
+@ CHECK-ARM: ldr r0, .Ltmp[[TMP3:[0-9]+]]
+@ CHECK-DARWIN-ARM: ldr r0, Ltmp3
+@ CHECK-THUMB2: ldr.w r0, .Ltmp[[TMP3:[0-9]+]]
+@ CHECK-DARWIN-THUMB2: ldr.w r0, Ltmp3
+@ CHECK-THUMB: error: instruction requires: thumb2
+@ CHECK-THUMB-NEXT:  ldr.w r0, =foo
+
+@ CHECK-LABEL: f3:
+f3:
+  ldr.w r1, =0x1
+@ CHECK-ARM: mov r1, #1
+@ CHECK-DARWIN-ARM: mov r1, #1
+@ CHECK-THUMB2: mov.w r1, #1
+@ CHECK-DARWIN-THUMB2: mov.w r1, #1
+@ CHECK-THUMB: error: instruction requires: thumb2
+@ CHECK-THUMB-NEXT:  ldr.w r1, =0x1
+
+@ CHECK: .Ltmp0:
+@ CHECK-NEXT: .long   65538
+@ CHECK: .Ltmp1:
+@ CHECK-NEXT: .long   65538
+@ CHECK: .Ltmp2:
+@ CHECK-NEXT: .long   foo
+@ CHECK: .Ltmp3:
+@ CHECK-NEXT: .long   foo
+
+@ CHECK-DARWIN: Ltmp0:
+@ CHECK-DARWIN-NEXT: .long   65538
+@ CHECK-DARWIN: Ltmp1:
+@ CHECK-DARWIN-NEXT: .long   65538
+@ CHECK-DARWIN: Ltmp2:
+@ CHECK-DARWIN-NEXT: .long   foo
+@ CHECK-DARWIN: Ltmp3:
+@ CHECK-DARWIN-NEXT: .long   foo