XCore target: Fix eliminateFrameIndex() to handle large frames

Large frame offsets are loaded from the ConstantPool.
Where possible, offsets are encoded using the smaller MKMSK instruction.
Large frame offsets can only be used when there is a frame-pointer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196085 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 42 insertions, 0 deletions

diff --git a/test/CodeGen/XCore/epilogue_prologue_fp.ll b/test/CodeGen/XCore/epilogue_prologue_fp.ll
new file mode 100644
index 0000000000..9b9837c90d
--- /dev/null
+++ b/test/CodeGen/XCore/epilogue_prologue_fp.ll
@@ -0,0 +1,42 @@
+; Functions with frames > 256K bytes require a frame pointer to access the stack.
+; At present, functions must be compiled using '-fno-omit-frame-pointer'.
+; RUN: llc < %s -march=xcore -disable-fp-elim | FileCheck %s
+
+declare void @f0(i32*)
+
+; CHECK: .section .cp.rodata.cst4,"aMc",@progbits,4
+; CHECK: .LCPI[[NUM:[0-9_]+]]:
+; CHECK: .long   99999
+; CHECK: .text
+; CHECK-LABEL:f1
+; CHECK:      entsp 65535
+; CHECK-NEXT: extsp 34465
+; CHECK-NEXT: stw r10, sp[1]
+; CHECK-NEXT: ldaw r10, sp[0]
+; CHECK-NEXT: ldw r1, cp[.LCPI[[NUM]]]
+; CHECK-NEXT: ldaw r0, r10[r1]
+; CHECK-NEXT: extsp 1
+; CHECK-NEXT: bl f0
+; CHECK-NEXT: ldaw sp, sp[1]
+; CHECK-NEXT: set sp, r10
+; CHECK-NEXT: ldw r10, sp[1]
+; CHECK-NEXT: ldaw sp, sp[65535]
+; CHECK-NEXT: retsp 34465
+define void @f1() nounwind {
+entry:
+  %0 = alloca [99998 x i32]
+  %1 = getelementptr inbounds [99998 x i32]* %0, i32 0, i32 99997
+  call void @f0(i32* %1)
+  ret void
+}
+
+; CHECK-LABEL:f2
+; CHECK:      mkmsk  [[REG:r[0-9]+]], 15
+; CHECK-NEXT: ldaw r0, r10{{\[}}[[REG]]{{\]}}
+define void @f2() nounwind {
+entry:
+  %0 = alloca [32768 x i32]
+  %1 = getelementptr inbounds [32768 x i32]* %0, i32 0, i32 32765
+  call void @f0(i32* %1)
+  ret void
+}