llvm-6502/test/CodeGen/XCore/unaligned_load.ll
Richard Osborne ccb7e96ef0 Expand unaligned 32 bit loads from an address which is a constant
offset from a 32 bit aligned base as follows:

  ldw low, base[offset >> 2]
  ldw high, base[(offset >> 2) + 1]
  shr low_shifted, low, (offset & 0x3) * 8
  shl high_shifted, high, 32 - (offset & 0x3) * 8
  or result, low_shifted, high_shifted

Expand 32 bit loads / stores with 16 bit alignment into two 16 bit
loads / stores.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75902 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-16 10:42:35 +00:00

32 lines
885 B
LLVM

; RUN: llvm-as < %s | llc -march=xcore > %t1.s
; RUN: grep "bl __misaligned_load" %t1.s | count 1
; RUN: grep ld16s %t1.s | count 2
; RUN: grep ldw %t1.s | count 2
; RUN: grep shl %t1.s | count 2
; RUN: grep shr %t1.s | count 1
; RUN: grep zext %t1.s | count 1
; RUN: grep "or " %t1.s | count 2
; Byte aligned load. Expands to call to __misaligned_load.
define i32 @align1(i32* %p) nounwind {
entry:
%0 = load i32* %p, align 1 ; <i32> [#uses=1]
ret i32 %0
}
; Half word aligned load. Expands to two 16bit loads.
define i32 @align2(i32* %p) nounwind {
entry:
%0 = load i32* %p, align 2 ; <i32> [#uses=1]
ret i32 %0
}
@a = global [5 x i8] zeroinitializer, align 4
; Constant offset from word aligned base. Expands to two 32bit loads.
define i32 @align3() nounwind {
entry:
%0 = load i32* bitcast (i8* getelementptr ([5 x i8]* @a, i32 0, i32 1) to i32*), align 1
ret i32 %0
}