1 # RUN: llc -run-pass postrapseudos -mtriple=i386-apple-macosx -o - %s | FileCheck %s 2 3 # Verify that we correctly save and restore eax when copying eflags, 4 # even when only a smaller alias of eax is used. We used to check only 5 # eax and not its aliases. 6 # PR27624. 7 8 --- | 9 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128" 10 11 define void @foo() { 12 entry: 13 br label %false 14 false: 15 ret void 16 } 17 18 ... 19 20 --- 21 name: foo 22 allVRegsAllocated: true 23 isSSA: false 24 tracksRegLiveness: true 25 liveins: 26 - { reg: '%edi' } 27 body: | 28 bb.0.entry: 29 liveins: %edi 30 successors: %bb.1.false 31 NOOP implicit-def %al 32 33 ; The bug was triggered only when LivePhysReg is used, which 34 ; happens only when the heuristic for the liveness computation 35 ; failed. The liveness computation heuristic looks at 10 instructions 36 ; before and after the copy. Make sure we do not reach the definition of 37 ; AL in 10 instructions, otherwise the heuristic will see that it is live. 38 NOOP 39 NOOP 40 NOOP 41 NOOP 42 NOOP 43 NOOP 44 NOOP 45 NOOP 46 NOOP 47 NOOP 48 NOOP 49 NOOP 50 NOOP 51 ; Save AL. 52 ; CHECK: PUSH32r killed %eax 53 54 ; Copy EDI into EFLAGS 55 ; CHECK-NEXT: %eax = MOV32rr %edi 56 ; CHECK-NEXT: %al = ADD8ri %al, 127, implicit-def %eflags 57 ; CHECK-NEXT: SAHF implicit-def %eflags, implicit %ah 58 %eflags = COPY %edi 59 60 ; Restore AL. 61 ; CHECK-NEXT: %eax = POP32r 62 bb.1.false: 63 liveins: %al 64 NOOP implicit %al 65 RETQ 66 67 ... 68
