120 lines
3.9 KiB
LLVM
120 lines
3.9 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -passes=instcombine -S | FileCheck %s
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;
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; Verify that the result of memchr calls used in equality expressions
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; with either the first argument or null are optimally folded.
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declare ptr @memchr(ptr, i32, i64)
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@a5 = constant [5 x i8] c"12345"
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; Fold memchr(a5, c, 5) == a5 to *a5 == c.
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define i1 @fold_memchr_a_c_5_eq_a(i32 %c) {
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; CHECK-LABEL: @fold_memchr_a_c_5_eq_a(
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; CHECK-NEXT: [[TMP1:%.*]] = trunc i32 [[C:%.*]] to i8
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; CHECK-NEXT: [[CHAR0CMP:%.*]] = icmp eq i8 [[TMP1]], 49
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; CHECK-NEXT: ret i1 [[CHAR0CMP]]
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;
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%q = call ptr @memchr(ptr @a5, i32 %c, i64 5)
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%cmp = icmp eq ptr %q, @a5
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ret i1 %cmp
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}
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; Fold memchr(a5, c, n) == a5 to n && *a5 == c. Unlike the case when
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; the first argument is an arbitrary, including potentially past-the-end,
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; pointer, this is safe because a5 is dereferenceable.
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define i1 @fold_memchr_a_c_n_eq_a(i32 %c, i64 %n) {
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; CHECK-LABEL: @fold_memchr_a_c_n_eq_a(
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; CHECK-NEXT: [[TMP1:%.*]] = trunc i32 [[C:%.*]] to i8
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; CHECK-NEXT: [[CHAR0CMP:%.*]] = icmp eq i8 [[TMP1]], 49
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i64 [[N:%.*]], 0
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; CHECK-NEXT: [[TMP3:%.*]] = select i1 [[TMP2]], i1 [[CHAR0CMP]], i1 false
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; CHECK-NEXT: ret i1 [[TMP3]]
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;
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%q = call ptr @memchr(ptr @a5, i32 %c, i64 %n)
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%cmp = icmp eq ptr %q, @a5
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ret i1 %cmp
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}
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; Do not fold memchr(a5 + i, c, n).
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define i1 @call_memchr_api_c_n_eq_a(i64 %i, i32 %c, i64 %n) {
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; CHECK-LABEL: @call_memchr_api_c_n_eq_a(
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; CHECK-NEXT: [[P:%.*]] = getelementptr [5 x i8], ptr @a5, i64 0, i64 [[I:%.*]]
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; CHECK-NEXT: [[Q:%.*]] = call ptr @memchr(ptr [[P]], i32 [[C:%.*]], i64 [[N:%.*]])
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; CHECK-NEXT: [[CMP:%.*]] = icmp eq ptr [[Q]], [[P]]
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; CHECK-NEXT: ret i1 [[CMP]]
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;
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%p = getelementptr [5 x i8], ptr @a5, i64 0, i64 %i
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%q = call ptr @memchr(ptr %p, i32 %c, i64 %n)
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%cmp = icmp eq ptr %q, %p
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ret i1 %cmp
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}
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; Fold memchr(s, c, 15) == s to *s == c.
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define i1 @fold_memchr_s_c_15_eq_s(ptr %s, i32 %c) {
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; CHECK-LABEL: @fold_memchr_s_c_15_eq_s(
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; CHECK-NEXT: [[TMP1:%.*]] = load i8, ptr [[S:%.*]], align 1
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; CHECK-NEXT: [[TMP2:%.*]] = trunc i32 [[C:%.*]] to i8
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; CHECK-NEXT: [[CHAR0CMP:%.*]] = icmp eq i8 [[TMP1]], [[TMP2]]
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; CHECK-NEXT: ret i1 [[CHAR0CMP]]
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;
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%p = call ptr @memchr(ptr %s, i32 %c, i64 15)
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%cmp = icmp eq ptr %p, %s
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ret i1 %cmp
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}
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; Fold memchr(s, c, 17) != s to *s != c.
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define i1 @fold_memchr_s_c_17_neq_s(ptr %s, i32 %c) {
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; CHECK-LABEL: @fold_memchr_s_c_17_neq_s(
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; CHECK-NEXT: [[TMP1:%.*]] = load i8, ptr [[S:%.*]], align 1
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; CHECK-NEXT: [[TMP2:%.*]] = trunc i32 [[C:%.*]] to i8
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; CHECK-NEXT: [[CHAR0CMP:%.*]] = icmp ne i8 [[TMP1]], [[TMP2]]
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; CHECK-NEXT: ret i1 [[CHAR0CMP]]
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;
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%p = call ptr @memchr(ptr %s, i32 %c, i64 17)
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%cmp = icmp ne ptr %p, %s
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ret i1 %cmp
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}
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; Fold memchr(s, c, n) == s to *s == c for nonzero n.
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define i1 @fold_memchr_s_c_nz_eq_s(ptr %s, i32 %c, i64 %n) {
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; CHECK-LABEL: @fold_memchr_s_c_nz_eq_s(
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; CHECK-NEXT: [[TMP1:%.*]] = load i8, ptr [[S:%.*]], align 1
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; CHECK-NEXT: [[TMP2:%.*]] = trunc i32 [[C:%.*]] to i8
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; CHECK-NEXT: [[CHAR0CMP:%.*]] = icmp eq i8 [[TMP1]], [[TMP2]]
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; CHECK-NEXT: ret i1 [[CHAR0CMP]]
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;
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%nz = or i64 %n, 1
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%p = call ptr @memchr(ptr %s, i32 %c, i64 %nz)
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%cmp = icmp eq ptr %p, %s
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ret i1 %cmp
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}
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; But do not fold memchr(s, c, n) as above if n might be zero. This could
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; be optimized to the equivalent of N && *S == C provided a short-circuiting
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; AND, otherwise the load could read a byte just past the end of an array.
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define i1 @call_memchr_s_c_n_eq_s(ptr %s, i32 %c, i64 %n) {
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; CHECK-LABEL: @call_memchr_s_c_n_eq_s(
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; CHECK-NEXT: [[P:%.*]] = call ptr @memchr(ptr [[S:%.*]], i32 [[C:%.*]], i64 [[N:%.*]])
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; CHECK-NEXT: [[CMP:%.*]] = icmp eq ptr [[P]], [[S]]
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; CHECK-NEXT: ret i1 [[CMP]]
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;
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%p = call ptr @memchr(ptr %s, i32 %c, i64 %n)
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%cmp = icmp eq ptr %p, %s
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ret i1 %cmp
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}
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