Allow remat of LI on PPC.

Allow load-immediates to be rematerialised in the register coalescer for
PPC. This makes test/CodeGen/PowerPC/big-endian-formal-args.ll fail,
because it relies on a register move getting emitted. The immediate load is
equivalent, so change this test case.

Patch by Tobias von Koch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162727 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 21 insertions, 3 deletions

diff --git a/lib/Target/PowerPC/PPCInstr64Bit.td b/lib/Target/PowerPC/PPCInstr64Bit.td
index c2351ec..94d709d 100644
--- a/lib/Target/PowerPC/PPCInstr64Bit.td
+++ b/lib/Target/PowerPC/PPCInstr64Bit.td
@@ -296,12 +296,14 @@ def MFLR8  : XFXForm_1_ext<31, 339, 8, (outs G8RC:$rT), (ins),
 
 let PPC970_Unit = 1 in {  // FXU Operations.
 
+let isReMaterializable = 1, isAsCheapAsAMove = 1, isMoveImm = 1 in {
 def LI8  : DForm_2_r0<14, (outs G8RC:$rD), (ins symbolLo64:$imm),
                       "li $rD, $imm", IntSimple,
                       [(set G8RC:$rD, immSExt16:$imm)]>;
 def LIS8 : DForm_2_r0<15, (outs G8RC:$rD), (ins symbolHi64:$imm),
                       "lis $rD, $imm", IntSimple,
                       [(set G8RC:$rD, imm16ShiftedSExt:$imm)]>;
+}
 
 // Logical ops.
 def NAND8: XForm_6<31, 476, (outs G8RC:$rA), (ins G8RC:$rS, G8RC:$rB),
diff --git a/lib/Target/PowerPC/PPCInstrInfo.td b/lib/Target/PowerPC/PPCInstrInfo.td
index 0230b4e..864b13a 100644
--- a/lib/Target/PowerPC/PPCInstrInfo.td
+++ b/lib/Target/PowerPC/PPCInstrInfo.td
@@ -972,7 +972,7 @@ def SUBFIC : DForm_2< 8, (outs GPRC:$rD), (ins GPRC:$rA, s16imm:$imm),
                      [(set GPRC:$rD, (subc immSExt16:$imm, GPRC:$rA))]>;
 }
 
-let isReMaterializable = 1 in {
+let isReMaterializable = 1, isAsCheapAsAMove = 1, isMoveImm = 1 in {
   def LI  : DForm_2_r0<14, (outs GPRC:$rD), (ins symbolLo:$imm),
                        "li $rD, $imm", IntSimple,
                        [(set GPRC:$rD, immSExt16:$imm)]>;
diff --git a/test/CodeGen/PowerPC/big-endian-formal-args.ll b/test/CodeGen/PowerPC/big-endian-formal-args.ll
index 9a456b6..638059a 100644
--- a/test/CodeGen/PowerPC/big-endian-formal-args.ll
+++ b/test/CodeGen/PowerPC/big-endian-formal-args.ll
@@ -2,10 +2,10 @@
 
 declare void @bar(i64 %x, i64 %y)
 
-; CHECK: li {{[53]}}, 0
+; CHECK: li 3, 0
 ; CHECK: li 4, 2
+; CHECK: li 5, 0
 ; CHECK: li 6, 3
-; CHECK: mr {{[53]}}, {{[53]}}
 
 define void @foo() {
   call void @bar(i64 2, i64 3)
diff --git a/test/CodeGen/PowerPC/remat-imm.ll b/test/CodeGen/PowerPC/remat-imm.ll
new file mode 100644
index 0000000..520921f
--- /dev/null
+++ b/test/CodeGen/PowerPC/remat-imm.ll
@@ -0,0 +1,16 @@
+; RUN: llc < %s | FileCheck %s
+; ModuleID = 'test.c'
+target datalayout = "E-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v128:128:128-n32"
+target triple = "powerpc-unknown-linux"
+
+@.str = private unnamed_addr constant [6 x i8] c"%d,%d\00", align 1
+
+define i32 @main() nounwind {
+entry:
+; CHECK: li 4, 128
+; CHECK-NOT: mr 4, {{.*}}
+  %call = tail call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([6 x i8]* @.str, i32 0, i32 0), i32 128, i32 128) nounwind
+  ret i32 0
+}
+
+declare i32 @printf(i8* nocapture, ...) nounwind