llvm-6502/test/CodeGen/ARM64/const-addr.ll
Tim Northover fef8e383eb ARM64: use 32-bit moves for constants where possible.
If we know that a particular 64-bit constant has all high bits zero, then we
can rely on the fact that 32-bit ARM64 instructions automatically zero out the
high bits of an x-register. This gives the expansion logic less constraints to
satisfy and so sometimes allows it to pick better sequences.

Came up while porting test/CodeGen/AArch64/movw-consts.ll: this will allow a
32-bit MOVN to be used in @test8 soon.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206379 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-16 11:52:51 +00:00

24 lines
662 B
LLVM

; RUN: llc -mtriple=arm64-darwin-unknown < %s | FileCheck %s
%T = type { i32, i32, i32, i32 }
; Test if the constant base address gets only materialized once.
define i32 @test1() nounwind {
; CHECK-LABEL: test1
; CHECK: movz w8, #1039, lsl #16
; CHECK-NEXT: movk w8, #49152
; CHECK-NEXT: ldp w9, w10, [x8, #4]
; CHECK: ldr w8, [x8, #12]
%at = inttoptr i64 68141056 to %T*
%o1 = getelementptr %T* %at, i32 0, i32 1
%t1 = load i32* %o1
%o2 = getelementptr %T* %at, i32 0, i32 2
%t2 = load i32* %o2
%a1 = add i32 %t1, %t2
%o3 = getelementptr %T* %at, i32 0, i32 3
%t3 = load i32* %o3
%a2 = add i32 %a1, %t3
ret i32 %a2
}