1; RUN: llc < %s -mtriple=arm-eabi -mattr=+v4t -O0 | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK_O0 2; RUN: llc < %s -mtriple=arm-eabi -mattr=+v4t -O1 | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK_O1 3 4; In /O0, the addition must not be eliminated. This happens when the load 5; and store are folded by the DAGCombiner. In /O1 and above, the optimization 6; must be executed. 7 8; CHECK-LABEL: {{^}}main 9; CHECK: mov [[TMP:r[0-9]+]], #0 10; CHECK-NEXT: str [[TMP]], [sp, #4] 11; CHECK_O0: str [[TMP]], [sp] 12; CHECK_O0: ldr [[TMP:r[0-9]+]], [sp] 13; CHECK_O0-NEXT: add [[TMP]], [[TMP]], #2 14; CHECK_O1-NOT: ldr [[TMP:r[0-9]+]], [sp] 15; CHECK_O1-NOT: add [[TMP]], [[TMP]], #2 16 17define i32 @main() { 18bb: 19 %tmp = alloca i32, align 4 20 %tmp1 = alloca i32, align 4 21 store i32 0, i32* %tmp, align 4 22 store i32 0, i32* %tmp1, align 4 23 %tmp2 = load i32, i32* %tmp1, align 4 24 %tmp3 = add nsw i32 %tmp2, 2 25 store i32 %tmp3, i32* %tmp1, align 4 26 %tmp4 = load i32, i32* %tmp1, align 4 27 %tmp5 = icmp eq i32 %tmp4, 2 28 br i1 %tmp5, label %bb6, label %bb7 29 30bb6: ; preds = %bb 31 store i32 0, i32* %tmp, align 4 32 br label %bb8 33 34bb7: ; preds = %bb 35 store i32 5, i32* %tmp, align 4 36 br label %bb8 37 38bb8: ; preds = %bb7, %bb6 39 %tmp9 = load i32, i32* %tmp, align 4 40 ret i32 %tmp9 41} 42