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llvm-mirror/test/CodeGen/SystemZ/unaligned-01.ll
Richard Sandiford ce09e57709 [SystemZ] Set usaAA to true
useAA significantly improves the handling of vector code that has TBAA
information attached.  It also helps other cases, as shown by the testsuite
changes here.  The only real downside I've seen is that it interferes with
MergeConsecutiveStores.  The problem is that that optimization works top
down, starting at the first store in the chain, and looks for cases where
the chain result is only used by a single related store.  These related
stores don't alias, so useAA will have rewritten all the later stores to
use a different chain input (typically the same one as the first store).

I think the advantages outweigh the disadvantages though, so for now I've
just disabled alias analysis for the unaligned-01.ll test.

llvm-svn: 193521
2013-10-28 13:53:37 +00:00

63 lines
1.7 KiB
LLVM

; Check that unaligned accesses are allowed in general. We check the
; few exceptions (like CRL) in their respective test files.
;
; FIXME: -combiner-alias-analysis (the default for SystemZ) stops
; f1 from being optimized.
; RUN: llc < %s -mtriple=s390x-linux-gnu -combiner-alias-analysis=false \
; RUN: | FileCheck %s
; Check that these four byte stores become a single word store.
define void @f1(i8 *%ptr) {
; CHECK: f1
; CHECK: iilf [[REG:%r[0-5]]], 66051
; CHECK: st [[REG]], 0(%r2)
; CHECK: br %r14
%off1 = getelementptr i8 *%ptr, i64 1
%off2 = getelementptr i8 *%ptr, i64 2
%off3 = getelementptr i8 *%ptr, i64 3
store i8 0, i8 *%ptr
store i8 1, i8 *%off1
store i8 2, i8 *%off2
store i8 3, i8 *%off3
ret void
}
; Check that unaligned 2-byte accesses are allowed.
define i16 @f2(i16 *%src, i16 *%dst) {
; CHECK-LABEL: f2:
; CHECK: lh %r2, 0(%r2)
; CHECK: sth %r2, 0(%r3)
; CHECK: br %r14
%val = load i16 *%src, align 1
store i16 %val, i16 *%dst, align 1
ret i16 %val
}
; Check that unaligned 4-byte accesses are allowed.
define i32 @f3(i32 *%src1, i32 *%src2, i32 *%dst) {
; CHECK-LABEL: f3:
; CHECK: l %r2, 0(%r2)
; CHECK: s %r2, 0(%r3)
; CHECK: st %r2, 0(%r4)
; CHECK: br %r14
%val1 = load i32 *%src1, align 1
%val2 = load i32 *%src2, align 2
%sub = sub i32 %val1, %val2
store i32 %sub, i32 *%dst, align 1
ret i32 %sub
}
; Check that unaligned 8-byte accesses are allowed.
define i64 @f4(i64 *%src1, i64 *%src2, i64 *%dst) {
; CHECK-LABEL: f4:
; CHECK: lg %r2, 0(%r2)
; CHECK: sg %r2, 0(%r3)
; CHECK: stg %r2, 0(%r4)
; CHECK: br %r14
%val1 = load i64 *%src1, align 1
%val2 = load i64 *%src2, align 2
%sub = sub i64 %val1, %val2
store i64 %sub, i64 *%dst, align 4
ret i64 %sub
}