1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py 2; Verify that calls to memcmp with counts in excess of the array sizes are 3; either folded gracefully or expanded to library calls. 4; 5; RUN: opt < %s -passes=instcombine -S -data-layout="E" | FileCheck %s --check-prefixes=BE 6; RUN: opt < %s -passes=instcombine -S -data-layout="e" | FileCheck %s --check-prefixes=LE 7 8declare i32 @memcmp(ptr, ptr, i64) 9 10@ia16a = constant [4 x i16] [i16 24930, i16 25444, i16 25958, i16 26472] 11@ia16b = constant [5 x i16] [i16 24930, i16 25444, i16 25958, i16 26472, i16 26992] 12@ia16c = constant [6 x i16] [i16 24930, i16 25444, i16 25958, i16 26472, i16 26993, i16 29042] 13 14 15; Fold calls with a count in excess of the size of one of the arrays that 16; differ. They're strictly undefined but folding the result to the expected 17; value (analogous to strncmp) is safer than letting a SIMD library 18; implementation return a bogus value. 19 20define void @fold_memcmp_mismatch_too_big(ptr %pcmp) { 21; BE-LABEL: @fold_memcmp_mismatch_too_big( 22; BE-NEXT: store i32 -1, ptr [[PCMP:%.*]], align 4 23; BE-NEXT: [[PSTOR_CB:%.*]] = getelementptr i8, ptr [[PCMP]], i64 4 24; BE-NEXT: store i32 1, ptr [[PSTOR_CB]], align 4 25; BE-NEXT: ret void 26; 27; LE-LABEL: @fold_memcmp_mismatch_too_big( 28; LE-NEXT: store i32 -1, ptr [[PCMP:%.*]], align 4 29; LE-NEXT: [[PSTOR_CB:%.*]] = getelementptr i8, ptr [[PCMP]], i64 4 30; LE-NEXT: store i32 1, ptr [[PSTOR_CB]], align 4 31; LE-NEXT: ret void 32; 33 34 %cmp_bc = call i32 @memcmp(ptr @ia16b, ptr @ia16c, i64 12) 35 store i32 %cmp_bc, ptr %pcmp 36 37 %cmp_cb = call i32 @memcmp(ptr @ia16c, ptr @ia16b, i64 12) 38 %pstor_cb = getelementptr i32, ptr %pcmp, i64 1 39 store i32 %cmp_cb, ptr %pstor_cb 40 41 ret void 42} 43 44 45; Fold even calls with excessive byte counts of arrays with matching bytes. 46; Like in the instances above, this is preferable to letting the undefined 47; calls take place, although it does prevent sanitizers from detecting them. 48 49define void @fold_memcmp_match_too_big(ptr %pcmp) { 50; BE-LABEL: @fold_memcmp_match_too_big( 51; BE-NEXT: store i32 0, ptr [[PCMP:%.*]], align 4 52; BE-NEXT: [[PSTOR_AB_M1:%.*]] = getelementptr i8, ptr [[PCMP]], i64 4 53; BE-NEXT: store i32 0, ptr [[PSTOR_AB_M1]], align 4 54; BE-NEXT: ret void 55; 56; LE-LABEL: @fold_memcmp_match_too_big( 57; LE-NEXT: store i32 0, ptr [[PCMP:%.*]], align 4 58; LE-NEXT: [[PSTOR_AB_M1:%.*]] = getelementptr i8, ptr [[PCMP]], i64 4 59; LE-NEXT: store i32 0, ptr [[PSTOR_AB_M1]], align 4 60; LE-NEXT: ret void 61; 62 63 %cmp_ab_9 = call i32 @memcmp(ptr @ia16a, ptr @ia16b, i64 9) 64 store i32 %cmp_ab_9, ptr %pcmp 65 66 %cmp_ab_m1 = call i32 @memcmp(ptr @ia16a, ptr @ia16b, i64 -1) 67 %pstor_ab_m1 = getelementptr i32, ptr %pcmp, i64 1 68 store i32 %cmp_ab_m1, ptr %pstor_ab_m1 69 70 ret void 71} 72