[PATCH] Use movw/movt instead of constant pool loads to lower byval parameter copies

[Derek Schuff]

- tnorthover review


http://reviews.llvm.org/D8442

Files:
  lib/Target/ARM/ARMISelLowering.cpp
  test/CodeGen/ARM/struct_byval.ll

Index: lib/Target/ARM/ARMISelLowering.cpp
===================================================================
--- lib/Target/ARM/ARMISelLowering.cpp
+++ lib/Target/ARM/ARMISelLowering.cpp
@@ -7140,16 +7140,20 @@
 
   // Load an immediate to varEnd.
   unsigned varEnd = MRI.createVirtualRegister(TRC);
-  if (IsThumb2) {
+  if (Subtarget->useMovt(*MF)) {
     unsigned Vtmp = varEnd;
     if ((LoopSize & 0xFFFF0000) != 0)
       Vtmp = MRI.createVirtualRegister(TRC);
-    AddDefaultPred(BuildMI(BB, dl, TII->get(ARM::t2MOVi16), Vtmp)
-                       .addImm(LoopSize & 0xFFFF));
+    AddDefaultPred(BuildMI(BB, dl,
+                           TII->get(IsThumb2 ? ARM::t2MOVi16 : ARM::MOVi16),
+                           Vtmp).addImm(LoopSize & 0xFFFF));
 
     if ((LoopSize & 0xFFFF0000) != 0)
-      AddDefaultPred(BuildMI(BB, dl, TII->get(ARM::t2MOVTi16), varEnd)
-                         .addReg(Vtmp).addImm(LoopSize >> 16));
+      AddDefaultPred(BuildMI(BB, dl,
+                             TII->get(IsThumb2 ? ARM::t2MOVTi16 : ARM::MOVTi16),
+                             varEnd)
+                         .addReg(Vtmp)
+                         .addImm(LoopSize >> 16));
   } else {
     MachineConstantPool *ConstantPool = MF->getConstantPool();
     Type *Int32Ty = Type::getInt32Ty(MF->getFunction()->getContext());
Index: test/CodeGen/ARM/struct_byval.ll
===================================================================
--- test/CodeGen/ARM/struct_byval.ll
+++ test/CodeGen/ARM/struct_byval.ll
@@ -1,5 +1,9 @@
 ; RUN: llc < %s -mtriple=armv7-apple-ios6.0 | FileCheck %s
 ; RUN: llc < %s -mtriple=thumbv7-apple-ios6.0 | FileCheck %s -check-prefix=THUMB
+; RUN: llc < %s -mtriple=armv7-unknown-nacl-gnueabi | FileCheck %s -check-prefix=NACL
+; RUN: llc < %s -mtriple=armv5-none-linux-gnueabi | FileCheck %s -check-prefix=NOMOVT
+
+; NOMOVT-NOT: movt
 
 ; rdar://9877866
 %struct.SmallStruct = type { i32, [8 x i32], [37 x i8] }
@@ -33,6 +37,14 @@
 ; THUMB: sub
 ; THUMB: str
 ; THUMB: bne
+; NACL-LABEL: g:
+; Ensure that use movw instead of constpool for the loop trip count. But don't
+; match the __stack_chk_guard movw
+; NACL: movw r{{[1-9]}}, #
+; NACL: ldr
+; NACL: sub
+; NACL: str
+; NACL: bne
   %st = alloca %struct.LargeStruct, align 4
   %call = call i32 @e2(%struct.LargeStruct* byval %st)
   ret i32 0
@@ -51,6 +63,11 @@
 ; THUMB: sub
 ; THUMB: vst1
 ; THUMB: bne
+; NACL: movw r{{[1-9]}}, #
+; NACL: vld1
+; NACL: sub
+; NACL: vst1
+; NACL: bne
   %st = alloca %struct.LargeStruct, align 16
   %call = call i32 @e3(%struct.LargeStruct* byval align 16 %st)
   ret i32 0

EMAIL PREFERENCES
  http://reviews.llvm.org/settings/panel/emailpreferences/
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D8442.22586.patch
Type: text/x-patch
Size: 2612 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20150324/84cba13a/attachment.bin>