; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
;
; Verify that snprintf calls with a constant size not exceeding INT_MAX
; and a "%c" format string are transformed into a store of the character.
; Also verify that a size in excess of INT_MAX prevents the transformation.
;
; RUN: opt < %s -passes=instcombine -S | FileCheck %s
@pcnt_c = constant [3 x i8] c"%c\00"
@adst = external global [0 x ptr]
@asiz = external global [0 x i32]
declare i32 @snprintf(ptr, i64, ptr, ...)
; Verify that all snprintf calls with a bound between INT_MAX and down
; to 0 are transformed to memcpy.
define void @fold_snprintf_pcnt_c(i32 %c) {
; CHECK-LABEL: @fold_snprintf_pcnt_c(
; CHECK-NEXT: [[PDIMAX:%.*]] = load ptr, ptr @adst, align 8
; CHECK-NEXT: store i8 1, ptr [[PDIMAX]], align 1
; CHECK-NEXT: [[NUL:%.*]] = getelementptr inbounds i8, ptr [[PDIMAX]], i64 1
; CHECK-NEXT: store i8 0, ptr [[NUL]], align 1
; CHECK-NEXT: store i32 1, ptr @asiz, align 4
; CHECK-NEXT: [[PD2:%.*]] = load ptr, ptr getelementptr (i8, ptr @adst, i64 8), align 8
; CHECK-NEXT: store i8 2, ptr [[PD2]], align 1
; CHECK-NEXT: [[NUL1:%.*]] = getelementptr inbounds i8, ptr [[PD2]], i64 1
; CHECK-NEXT: store i8 0, ptr [[NUL1]], align 1
; CHECK-NEXT: store i32 1, ptr getelementptr (i8, ptr @asiz, i64 4), align 4
; CHECK-NEXT: [[PD2_0:%.*]] = load ptr, ptr getelementptr (i8, ptr @adst, i64 16), align 8
; CHECK-NEXT: store i8 0, ptr [[PD2_0]], align 1
; CHECK-NEXT: [[NUL2:%.*]] = getelementptr inbounds i8, ptr [[PD2_0]], i64 1
; CHECK-NEXT: store i8 0, ptr [[NUL2]], align 1
; CHECK-NEXT: store i32 1, ptr getelementptr (i8, ptr @asiz, i64 8), align 4
; CHECK-NEXT: [[PD1:%.*]] = load ptr, ptr getelementptr (i8, ptr @adst, i64 24), align 8
; CHECK-NEXT: store i8 0, ptr [[PD1]], align 1
; CHECK-NEXT: store i32 1, ptr getelementptr (i8, ptr @asiz, i64 12), align 4
; CHECK-NEXT: store i32 1, ptr getelementptr (i8, ptr @asiz, i64 16), align 4
; CHECK-NEXT: [[PD2_C:%.*]] = load ptr, ptr getelementptr (i8, ptr @adst, i64 32), align 8
; CHECK-NEXT: [[CHAR:%.*]] = trunc i32 [[C:%.*]] to i8
; CHECK-NEXT: store i8 [[CHAR]], ptr [[PD2_C]], align 1
; CHECK-NEXT: [[NUL3:%.*]] = getelementptr inbounds i8, ptr [[PD2_C]], i64 1
; CHECK-NEXT: store i8 0, ptr [[NUL3]], align 1
; CHECK-NEXT: store i32 1, ptr getelementptr (i8, ptr @asiz, i64 16), align 4
; CHECK-NEXT: [[PD1_C:%.*]] = load ptr, ptr getelementptr (i8, ptr @adst, i64 40), align 8
; CHECK-NEXT: store i8 0, ptr [[PD1_C]], align 1
; CHECK-NEXT: store i32 1, ptr getelementptr (i8, ptr @asiz, i64 20), align 4
; CHECK-NEXT: ret void
;
; Transform snprintf(dst, INT_MAX, "%c", 1) to memcpy(dst, "1", 2), 1.
%pdimax = load ptr, ptr @adst
%nimax = call i32 (ptr, i64, ptr, ...) @snprintf(ptr %pdimax, i64 2147483647, ptr @pcnt_c, i32 1)
store i32 %nimax, ptr @asiz
; Transform snprintf(dst, 2, "%c", '\2') to memcpy(dst, "2", 2), 1.
%pd2 = load ptr, ptr getelementptr ([0 x ptr], ptr @adst, i32 0, i32 1)
%n2 = call i32 (ptr, i64, ptr, ...) @snprintf(ptr %pd2, i64 2, ptr @pcnt_c, i8 2)
store i32 %n2, ptr getelementptr ([0 x i32], ptr @asiz, i32 0, i32 1)
; Transform snprintf(dst, 2, "%c", '\0') to memcpy(dst, "\0", 2), 1.
%pd2_0 = load ptr, ptr getelementptr ([0 x ptr], ptr @adst, i32 0, i32 2)
%n2_0 = call i32 (ptr, i64, ptr, ...) @snprintf(ptr %pd2_0, i64 2, ptr @pcnt_c, i8 0)
store i32 %n2_0, ptr getelementptr ([0 x i32], ptr @asiz, i32 0, i32 2)
; Transform snprintf(dst, 1, "%c", (short)3) to memcpy(dst, "\3", 2), 1.
%pd1 = load ptr, ptr getelementptr ([0 x ptr], ptr @adst, i32 0, i32 3)
%n1 = call i32 (ptr, i64, ptr, ...) @snprintf(ptr %pd1, i64 1, ptr @pcnt_c, i16 3)
store i32 %n1, ptr getelementptr ([0 x i32], ptr @asiz, i32 0, i32 3)
; Fold snprintf(dst, 0, "%c", 4) to 1.
%pd0 = load ptr, ptr getelementptr ([0 x ptr], ptr @adst, i32 0, i32 4)
%n0 = call i32 (ptr, i64, ptr, ...) @snprintf(ptr %pd0, i64 0, ptr @pcnt_c, i32 4)
store i32 %n0, ptr getelementptr ([0 x i32], ptr @asiz, i32 0, i32 4)
; Transform snprintf(dst, 2, "%c", c) with a nonconstant c to
; dst[0] = c, dst[1] = '\0', 1.
%pd2_c = load ptr, ptr getelementptr ([0 x ptr], ptr @adst, i32 0, i32 4)
%n2_c = call i32 (ptr, i64, ptr, ...) @snprintf(ptr %pd2_c, i64 2, ptr @pcnt_c, i32 %c)
store i32 %n2_c, ptr getelementptr ([0 x i32], ptr @asiz, i32 0, i32 4)
; Transform snprintf(dst, 1, "%c", c) with a nonconstant c to *dst = '\0', 0.
%pd1_c = load ptr, ptr getelementptr ([0 x ptr], ptr @adst, i32 0, i32 5)
%n1_c = call i32 (ptr, i64, ptr, ...) @snprintf(ptr %pd1_c, i64 1, ptr @pcnt_c, i32 %c)
store i32 %n1_c, ptr getelementptr ([0 x i32], ptr @asiz, i32 0, i32 5)
ret void
}
; Verify that snprintf calls with a bound greater than INT_MAX are not
; transformed. POSIX requires implementations to set errno to EOVERFLOW
; so such calls could be folded to just that followed by returning -1.
define void @call_snprintf_pcnt_c_ximax(i32 %c) {
; CHECK-LABEL: @call_snprintf_pcnt_c_ximax(
; CHECK-NEXT: [[PDM1:%.*]] = load ptr, ptr @adst, align 8
; CHECK-NEXT: [[NM1:%.*]] = call i32 (ptr, i64, ptr, ...) @snprintf(ptr noundef nonnull dereferenceable(1) [[PDM1]], i64 -1, ptr nonnull @pcnt_c, i8 0)
; CHECK-NEXT: store i32 [[NM1]], ptr @asiz, align 4
; CHECK-NEXT: [[PDIMAXP1:%.*]] = load ptr, ptr getelementptr (i8, ptr @adst, i64 8), align 8
; CHECK-NEXT: [[NIMAXP1:%.*]] = call i32 (ptr, i64, ptr, ...) @snprintf(ptr noundef nonnull dereferenceable(1) [[PDIMAXP1]], i64 2147483648, ptr nonnull @pcnt_c, i8 1)
; CHECK-NEXT: store i32 [[NIMAXP1]], ptr getelementptr (i8, ptr @asiz, i64 4), align 4
; CHECK-NEXT: [[PDM1SL32:%.*]] = load ptr, ptr getelementptr (i8, ptr @adst, i64 16), align 8
; CHECK-NEXT: [[NM1SL32:%.*]] = call i32 (ptr, i64, ptr, ...) @snprintf(ptr noundef nonnull dereferenceable(1) [[PDM1SL32]], i64 -4294967296, ptr nonnull @pcnt_c, i8 1)
; CHECK-NEXT: store i32 [[NM1SL32]], ptr getelementptr (i8, ptr @asiz, i64 8), align 4
; CHECK-NEXT: ret void
;
%pdm1 = load ptr, ptr @adst
%nm1 = call i32 (ptr, i64, ptr, ...) @snprintf(ptr %pdm1, i64 -1, ptr @pcnt_c, i8 0)
store i32 %nm1, ptr @asiz
%pdimaxp1 = load ptr, ptr getelementptr ([0 x ptr], ptr @adst, i32 0, i32 1)
%nimaxp1 = call i32 (ptr, i64, ptr, ...) @snprintf(ptr %pdimaxp1, i64 2147483648, ptr @pcnt_c, i8 1)
store i32 %nimaxp1, ptr getelementptr ([0 x i32], ptr @asiz, i32 0, i32 1)
; Exercise snprintf(dst, -1LU << 32, "%c", c).
%pdm1sl32 = load ptr, ptr getelementptr ([0 x ptr], ptr @adst, i32 0, i32 2)
%nm1sl32 = call i32 (ptr, i64, ptr, ...) @snprintf(ptr %pdm1sl32, i64 18446744069414584320, ptr @pcnt_c, i8 1)
store i32 %nm1sl32, ptr getelementptr ([0 x i32], ptr @asiz, i32 0, i32 2)
ret void
}
Codebase Browser
llvm