1*9880d681SAndroid Build Coastguard Worker; RUN: llc < %s -mtriple=thumbv7-apple-ios -mcpu=cortex-a8 | FileCheck %s 2*9880d681SAndroid Build Coastguard Worker 3*9880d681SAndroid Build Coastguard Worker; ARM has a peephole optimization which looks for a def / use pair. The def 4*9880d681SAndroid Build Coastguard Worker; produces a 32-bit immediate which is consumed by the use. It tries to 5*9880d681SAndroid Build Coastguard Worker; fold the immediate by breaking it into two parts and fold them into the 6*9880d681SAndroid Build Coastguard Worker; immmediate fields of two uses. e.g 7*9880d681SAndroid Build Coastguard Worker; movw r2, #40885 8*9880d681SAndroid Build Coastguard Worker; movt r3, #46540 9*9880d681SAndroid Build Coastguard Worker; add r0, r0, r3 10*9880d681SAndroid Build Coastguard Worker; => 11*9880d681SAndroid Build Coastguard Worker; add.w r0, r0, #3019898880 12*9880d681SAndroid Build Coastguard Worker; add.w r0, r0, #30146560 13*9880d681SAndroid Build Coastguard Worker; 14*9880d681SAndroid Build Coastguard Worker; However, this transformation is incorrect if the user produces a flag. e.g. 15*9880d681SAndroid Build Coastguard Worker; movw r2, #40885 16*9880d681SAndroid Build Coastguard Worker; movt r3, #46540 17*9880d681SAndroid Build Coastguard Worker; adds r0, r0, r3 18*9880d681SAndroid Build Coastguard Worker; => 19*9880d681SAndroid Build Coastguard Worker; add.w r0, r0, #3019898880 20*9880d681SAndroid Build Coastguard Worker; adds.w r0, r0, #30146560 21*9880d681SAndroid Build Coastguard Worker; Note the adds.w may not set the carry flag even if the original sequence 22*9880d681SAndroid Build Coastguard Worker; would. 23*9880d681SAndroid Build Coastguard Worker; 24*9880d681SAndroid Build Coastguard Worker; rdar://11116189 25*9880d681SAndroid Build Coastguard Workerdefine i64 @t(i64 %aInput) nounwind { 26*9880d681SAndroid Build Coastguard Worker; CHECK-LABEL: t: 27*9880d681SAndroid Build Coastguard Worker; CHECK: movs [[REG:(r[0-9]+)]], #0 28*9880d681SAndroid Build Coastguard Worker; CHECK: movt [[REG]], #46540 29*9880d681SAndroid Build Coastguard Worker; CHECK: adds r{{[0-9]+}}, r{{[0-9]+}}, [[REG]] 30*9880d681SAndroid Build Coastguard Worker %1 = mul i64 %aInput, 1000000 31*9880d681SAndroid Build Coastguard Worker %2 = add i64 %1, -7952618389194932224 32*9880d681SAndroid Build Coastguard Worker ret i64 %2 33*9880d681SAndroid Build Coastguard Worker} 34