1; RUN: llc < %s -asm-verbose=false -verify-machineinstrs | FileCheck %s 2 3; Test the register stackifier pass. 4 5target datalayout = "e-p:32:32-i64:64-n32:64-S128" 6target triple = "wasm32-unknown-unknown" 7 8; No because of pointer aliasing. 9 10; CHECK-LABEL: no0: 11; CHECK: return $1{{$}} 12define i32 @no0(i32* %p, i32* %q) { 13 %t = load i32, i32* %q 14 store i32 0, i32* %p 15 ret i32 %t 16} 17 18; No because of side effects. 19 20; CHECK-LABEL: no1: 21; CHECK: return $1{{$}} 22define i32 @no1(i32* %p, i32* dereferenceable(4) %q) { 23 %t = load volatile i32, i32* %q, !invariant.load !0 24 store volatile i32 0, i32* %p 25 ret i32 %t 26} 27 28; Yes because of invariant load and no side effects. 29 30; CHECK-LABEL: yes0: 31; CHECK: return $pop0{{$}} 32define i32 @yes0(i32* %p, i32* dereferenceable(4) %q) { 33 %t = load i32, i32* %q, !invariant.load !0 34 store i32 0, i32* %p 35 ret i32 %t 36} 37 38; Yes because of no intervening side effects. 39 40; CHECK-LABEL: yes1: 41; CHECK: return $pop0{{$}} 42define i32 @yes1(i32* %q) { 43 %t = load volatile i32, i32* %q 44 ret i32 %t 45} 46 47; Don't schedule stack uses into the stack. To reduce register pressure, the 48; scheduler might be tempted to move the definition of $2 down. However, this 49; would risk getting incorrect liveness if the instructions are later 50; rearranged to make the stack contiguous. 51 52; CHECK-LABEL: stack_uses: 53; CHECK-NEXT: .param i32, i32, i32, i32{{$}} 54; CHECK-NEXT: .result i32{{$}} 55; CHECK-NEXT: .local i32, i32{{$}} 56; CHECK-NEXT: i32.const $4=, 1{{$}} 57; CHECK-NEXT: i32.const $5=, 2{{$}} 58; CHECK-NEXT: i32.lt_s $push0=, $0, $4{{$}} 59; CHECK-NEXT: i32.lt_s $push1=, $1, $5{{$}} 60; CHECK-NEXT: i32.xor $push4=, $pop0, $pop1{{$}} 61; CHECK-NEXT: i32.lt_s $push2=, $2, $4{{$}} 62; CHECK-NEXT: i32.lt_s $push3=, $3, $5{{$}} 63; CHECK-NEXT: i32.xor $push5=, $pop2, $pop3{{$}} 64; CHECK-NEXT: i32.xor $push6=, $pop4, $pop5{{$}} 65; CHECK-NEXT: i32.ne $push7=, $pop6, $4{{$}} 66; CHECK-NEXT: block BB4_2{{$}} 67; CHECK-NEXT: br_if $pop7, BB4_2{{$}} 68; CHECK-NEXT: i32.const $push8=, 0{{$}} 69; CHECK-NEXT: return $pop8{{$}} 70; CHECK-NEXT: BB4_2: 71; CHECK-NEXT: return $4{{$}} 72define i32 @stack_uses(i32 %x, i32 %y, i32 %z, i32 %w) { 73entry: 74 %c = icmp sle i32 %x, 0 75 %d = icmp sle i32 %y, 1 76 %e = icmp sle i32 %z, 0 77 %f = icmp sle i32 %w, 1 78 %g = xor i1 %c, %d 79 %h = xor i1 %e, %f 80 %i = xor i1 %g, %h 81 br i1 %i, label %true, label %false 82true: 83 ret i32 0 84false: 85 ret i32 1 86} 87 88!0 = !{} 89