llvm/test/Transforms/InstSimplify/cast.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S -passes=instsimplify < %s | FileCheck %s
target datalayout = "p:32:32"

define i1 @test1(i1 %V) {
; CHECK-LABEL: @test1(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    ret i1 [[V:%.*]]
;
entry:
  %Z = zext i1 %V to i32
  %T = trunc i32 %Z to i1
  ret i1 %T
}

define ptr @test2(ptr %V) {
; CHECK-LABEL: @test2(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    ret ptr [[V:%.*]]
;
entry:
  ret ptr %V
}

define ptr @test3(ptr %V) {
; CHECK-LABEL: @test3(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    ret ptr [[V:%.*]]
;
entry:
  ret ptr %V
}

define i32 @test4() {
; CHECK-LABEL: @test4(
; CHECK-NEXT:    ret i32 4
;
  %alloca = alloca i32, align 4                                     ; alloca + 0
  %gep = getelementptr inbounds i32, ptr %alloca, i32 1            ; alloca + 4
  %pti = ptrtoint ptr %alloca to i32                               ; alloca
  %sub = sub i32 0, %pti                                            ; -alloca
  %add = getelementptr [4 x i8], ptr %gep, i32 0, i32 %sub     ; alloca + 4 - alloca == 4
  %add_to_int = ptrtoint ptr %add to i32                            ; 4
  ret i32 %add_to_int                                               ; 4
}

define i32 @test5() {
; CHECK-LABEL: @test5(
; CHECK-NEXT:    ret i32 3
;
  %alloca = alloca i32, align 4                                     ; alloca + 0
  %gep = getelementptr inbounds i32, ptr %alloca, i32 1            ; alloca + 4
  %pti = ptrtoint ptr %alloca to i32                               ; alloca
  %sub = xor i32 %pti, -1                                           ; ~alloca
  %add = getelementptr [4 x i8], ptr %gep, i32 0, i32 %sub     ; alloca + 4 - alloca - 1 == 3
  %add_to_int = ptrtoint ptr %add to i32                            ; 4
  ret i32 %add_to_int                                               ; 4
}

; A value-preserving zext of a no-unsigned-wrap trunc folds back to the source.
define i64 @zext_of_trunc_nuw(i64 %x) {
; CHECK-LABEL: @zext_of_trunc_nuw(
; CHECK-NEXT:    ret i64 [[X:%.*]]
;
  %t = trunc nuw i64 %x to i32
  %z = zext i32 %t to i64
  ret i64 %z
}

; A value-preserving sext of a no-signed-wrap trunc folds back to the source.
define i64 @sext_of_trunc_nsw(i64 %x) {
; CHECK-LABEL: @sext_of_trunc_nsw(
; CHECK-NEXT:    ret i64 [[X:%.*]]
;
  %t = trunc nsw i64 %x to i32
  %s = sext i32 %t to i64
  ret i64 %s
}

; Same folds work on vectors.
define <2 x i64> @zext_of_trunc_nuw_vec(<2 x i64> %x) {
; CHECK-LABEL: @zext_of_trunc_nuw_vec(
; CHECK-NEXT:    ret <2 x i64> [[X:%.*]]
;
  %t = trunc nuw <2 x i64> %x to <2 x i32>
  %z = zext <2 x i32> %t to <2 x i64>
  ret <2 x i64> %z
}

; Negative: without nuw, zext(trunc) is not value-preserving for InstSimplify.
define i64 @zext_of_trunc_no_flag(i64 %x) {
; CHECK-LABEL: @zext_of_trunc_no_flag(
; CHECK-NEXT:    [[T:%.*]] = trunc i64 [[X:%.*]] to i32
; CHECK-NEXT:    [[Z:%.*]] = zext i32 [[T]] to i64
; CHECK-NEXT:    ret i64 [[Z]]
;
  %t = trunc i64 %x to i32
  %z = zext i32 %t to i64
  ret i64 %z
}

; Negative: zext of an nsw-only trunc does not guarantee the unsigned round-trip.
define i64 @zext_of_trunc_nsw_only(i64 %x) {
; CHECK-LABEL: @zext_of_trunc_nsw_only(
; CHECK-NEXT:    [[T:%.*]] = trunc nsw i64 [[X:%.*]] to i32
; CHECK-NEXT:    [[Z:%.*]] = zext i32 [[T]] to i64
; CHECK-NEXT:    ret i64 [[Z]]
;
  %t = trunc nsw i64 %x to i32
  %z = zext i32 %t to i64
  ret i64 %z
}

; Negative: sext of an nuw-only trunc does not guarantee the signed round-trip.
define i64 @sext_of_trunc_nuw_only(i64 %x) {
; CHECK-LABEL: @sext_of_trunc_nuw_only(
; CHECK-NEXT:    [[T:%.*]] = trunc nuw i64 [[X:%.*]] to i32
; CHECK-NEXT:    [[S:%.*]] = sext i32 [[T]] to i64
; CHECK-NEXT:    ret i64 [[S]]
;
  %t = trunc nuw i64 %x to i32
  %s = sext i32 %t to i64
  ret i64 %s
}