llvm-project/llvm/test/CodeGen/WebAssembly/reg-stackify.ll

; RUN: llc < %s -asm-verbose=false | FileCheck %s

; Test the register stackifier pass.

target datalayout = "e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32-unknown-unknown"

; No because of pointer aliasing.

; CHECK-LABEL: no0:
; CHECK: return $1{{$}}
define i32 @no0(i32* %p, i32* %q) {
  %t = load i32, i32* %q
  store i32 0, i32* %p
  ret i32 %t
}

; No because of side effects.

; CHECK-LABEL: no1:
; CHECK: return $1{{$}}
define i32 @no1(i32* %p, i32* dereferenceable(4) %q) {
  %t = load volatile i32, i32* %q, !invariant.load !0
  store volatile i32 0, i32* %p
  ret i32 %t
}

; Yes because of invariant load and no side effects.

; CHECK-LABEL: yes0:
; CHECK: return $pop0{{$}}
define i32 @yes0(i32* %p, i32* dereferenceable(4) %q) {
  %t = load i32, i32* %q, !invariant.load !0
  store i32 0, i32* %p
  ret i32 %t
}

; Yes because of no intervening side effects.

; CHECK-LABEL: yes1:
; CHECK: return $pop0{{$}}
define i32 @yes1(i32* %q) {
  %t = load volatile i32, i32* %q
  ret i32 %t
}

; Don't schedule stack uses into the stack. To reduce register pressure, the
; scheduler might be tempted to move the definition of $2 down. However, this
; would risk getting incorrect liveness if the instructions are later
; rearranged to make the stack contiguous.

; CHECK-LABEL: stack_uses:
; CHECK-NEXT: .param i32{{$}}
; CHECK-NEXT: .result i32{{$}}
; CHECK-NEXT: local i32, i32{{$}}
; CHECK-NEXT: i32.const       $1=, 1{{$}}
; CHECK-NEXT: i32.const       $2=, 0{{$}}
; CHECK-NEXT: i32.and         $push0=, $0, $1{{$}}
; CHECK-NEXT: i32.eq          $push1=, $pop0, $2{{$}}
; CHECK-NEXT: block           BB4_2{{$}}
; CHECK-NEXT: br_if           $pop1, BB4_2{{$}}
; CHECK-NEXT: return          $2{{$}}
; CHECK-NEXT: BB4_2:{{$}}
; CHECK-NEXT: return          $1{{$}}
define i32 @stack_uses(i32 %x) {
entry:
  %c = trunc i32 %x to i1
  br i1 %c, label %true, label %false
true:
  ret i32 0
false:
  ret i32 1
}

!0 = !{}