test/CodeGen/X86/stores-merging.ll

; RUN: llc < %s | FileCheck %s

target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

%structTy = type { i8, i32, i32 }

@e = common global %structTy zeroinitializer, align 4

;; Ensure that MergeConsecutiveStores doesn't incorrectly reorder
;; store operations.  The first test stores in increasing address
;; order, the second in decreasing -- but in both cases should have
;; the same result in memory in the end.

; CHECK-LABEL: redundant_stores_merging:
; CHECK:   movl    $123, e+8(%rip)
; CHECK:   movabsq $1958505086977, %rax
; CHECK:   movq    %rax, e+4(%rip)
define void @redundant_stores_merging() {
entry:
  store i32 1, i32* getelementptr inbounds (%structTy, %structTy* @e, i64 0, i32 1), align 4
  store i32 123, i32* getelementptr inbounds (%structTy, %structTy* @e, i64 0, i32 2), align 4
  store i32 456, i32* getelementptr inbounds (%structTy, %structTy* @e, i64 0, i32 2), align 4
  ret void
}

;; This variant tests PR25154.
; CHECK-LABEL: redundant_stores_merging_reverse:
; CHECK:   movl    $123, e+8(%rip)
; CHECK:   movabsq $1958505086977, %rax
; CHECK:   movq    %rax, e+4(%rip)
define void @redundant_stores_merging_reverse() {
entry:
  store i32 123, i32* getelementptr inbounds (%structTy, %structTy* @e, i64 0, i32 2), align 4
  store i32 456, i32* getelementptr inbounds (%structTy, %structTy* @e, i64 0, i32 2), align 4
  store i32 1, i32* getelementptr inbounds (%structTy, %structTy* @e, i64 0, i32 1), align 4
  ret void
}

@b = common global [8 x i8] zeroinitializer, align 2

;; The 2-byte store to offset 3 overlaps the 2-byte store to offset 2;
;; these must not be reordered in MergeConsecutiveStores such that the
;; store to 3 comes first (e.g. by merging the stores to 0 and 2 into
;; a movl, after the store to 3).

;; CHECK-LABEL: overlapping_stores_merging:
;; CHECK:  movw    $0, b+2(%rip)
;; CHECK:  movw    $2, b+3(%rip)
;; CHECK:  movw    $1, b(%rip)
define void @overlapping_stores_merging() {
entry:
  store i16 0, i16* bitcast (i8* getelementptr inbounds ([8 x i8], [8 x i8]* @b, i64 0, i64 2) to i16*), align 2
  store i16 2, i16* bitcast (i8* getelementptr inbounds ([8 x i8], [8 x i8]* @b, i64 0, i64 3) to i16*), align 1
  store i16 1, i16* bitcast (i8* getelementptr inbounds ([8 x i8], [8 x i8]* @b, i64 0, i64 0) to i16*), align 2
  ret void
}