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