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bitfield.cpp
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bitfield.cpp
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// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s \
// RUN: | FileCheck -check-prefix=CHECK-X86-64 %s
// RUN: %clang_cc1 -triple powerpc64-unknown-unknown -emit-llvm -o - %s \
// RUN: | FileCheck -check-prefix=CHECK-PPC64 %s
//
// Tests for bitfield access patterns in C++ with special attention to
// conformance to C++11 memory model requirements.
namespace N0 {
// Test basic bitfield layout access across interesting byte and word
// boundaries on both little endian and big endian platforms.
struct __attribute__((packed)) S {
unsigned b00 : 14;
unsigned b01 : 2;
unsigned b20 : 6;
unsigned b21 : 2;
unsigned b30 : 30;
unsigned b31 : 2;
unsigned b70 : 6;
unsigned b71 : 2;
};
unsigned read00(S* s) {
// CHECK-X86-64-LABEL: define i32 @_ZN2N06read00
// CHECK-X86-64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-X86-64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-X86-64: %[[and:.*]] = and i64 %[[val]], 16383
// CHECK-X86-64: %[[trunc:.*]] = trunc i64 %[[and]] to i32
// CHECK-X86-64: ret i32 %[[trunc]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N06read00
// CHECK-PPC64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-PPC64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-PPC64: %[[shr:.*]] = lshr i64 %[[val]], 50
// CHECK-PPC64: %[[trunc:.*]] = trunc i64 %[[shr]] to i32
// CHECK-PPC64: ret i32 %[[trunc]]
return s->b00;
}
unsigned read01(S* s) {
// CHECK-X86-64-LABEL: define i32 @_ZN2N06read01
// CHECK-X86-64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-X86-64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-X86-64: %[[shr:.*]] = lshr i64 %[[val]], 14
// CHECK-X86-64: %[[and:.*]] = and i64 %[[shr]], 3
// CHECK-X86-64: %[[trunc:.*]] = trunc i64 %[[and]] to i32
// CHECK-X86-64: ret i32 %[[trunc]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N06read01
// CHECK-PPC64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-PPC64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-PPC64: %[[shr:.*]] = lshr i64 %[[val]], 48
// CHECK-PPC64: %[[and:.*]] = and i64 %[[shr]], 3
// CHECK-PPC64: %[[trunc:.*]] = trunc i64 %[[and]] to i32
// CHECK-PPC64: ret i32 %[[trunc]]
return s->b01;
}
unsigned read20(S* s) {
// CHECK-X86-64-LABEL: define i32 @_ZN2N06read20
// CHECK-X86-64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-X86-64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-X86-64: %[[shr:.*]] = lshr i64 %[[val]], 16
// CHECK-X86-64: %[[and:.*]] = and i64 %[[shr]], 63
// CHECK-X86-64: %[[trunc:.*]] = trunc i64 %[[and]] to i32
// CHECK-X86-64: ret i32 %[[trunc]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N06read20
// CHECK-PPC64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-PPC64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-PPC64: %[[shr:.*]] = lshr i64 %[[val]], 42
// CHECK-PPC64: %[[and:.*]] = and i64 %[[shr]], 63
// CHECK-PPC64: %[[trunc:.*]] = trunc i64 %[[and]] to i32
// CHECK-PPC64: ret i32 %[[trunc]]
return s->b20;
}
unsigned read21(S* s) {
// CHECK-X86-64-LABEL: define i32 @_ZN2N06read21
// CHECK-X86-64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-X86-64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-X86-64: %[[shr:.*]] = lshr i64 %[[val]], 22
// CHECK-X86-64: %[[and:.*]] = and i64 %[[shr]], 3
// CHECK-X86-64: %[[trunc:.*]] = trunc i64 %[[and]] to i32
// CHECK-X86-64: ret i32 %[[trunc]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N06read21
// CHECK-PPC64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-PPC64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-PPC64: %[[shr:.*]] = lshr i64 %[[val]], 40
// CHECK-PPC64: %[[and:.*]] = and i64 %[[shr]], 3
// CHECK-PPC64: %[[trunc:.*]] = trunc i64 %[[and]] to i32
// CHECK-PPC64: ret i32 %[[trunc]]
return s->b21;
}
unsigned read30(S* s) {
// CHECK-X86-64-LABEL: define i32 @_ZN2N06read30
// CHECK-X86-64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-X86-64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-X86-64: %[[shr:.*]] = lshr i64 %[[val]], 24
// CHECK-X86-64: %[[and:.*]] = and i64 %[[shr]], 1073741823
// CHECK-X86-64: %[[trunc:.*]] = trunc i64 %[[and]] to i32
// CHECK-X86-64: ret i32 %[[trunc]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N06read30
// CHECK-PPC64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-PPC64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-PPC64: %[[shr:.*]] = lshr i64 %[[val]], 10
// CHECK-PPC64: %[[and:.*]] = and i64 %[[shr]], 1073741823
// CHECK-PPC64: %[[trunc:.*]] = trunc i64 %[[and]] to i32
// CHECK-PPC64: ret i32 %[[trunc]]
return s->b30;
}
unsigned read31(S* s) {
// CHECK-X86-64-LABEL: define i32 @_ZN2N06read31
// CHECK-X86-64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-X86-64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-X86-64: %[[shr:.*]] = lshr i64 %[[val]], 54
// CHECK-X86-64: %[[and:.*]] = and i64 %[[shr]], 3
// CHECK-X86-64: %[[trunc:.*]] = trunc i64 %[[and]] to i32
// CHECK-X86-64: ret i32 %[[trunc]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N06read31
// CHECK-PPC64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-PPC64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-PPC64: %[[shr:.*]] = lshr i64 %[[val]], 8
// CHECK-PPC64: %[[and:.*]] = and i64 %[[shr]], 3
// CHECK-PPC64: %[[trunc:.*]] = trunc i64 %[[and]] to i32
// CHECK-PPC64: ret i32 %[[trunc]]
return s->b31;
}
unsigned read70(S* s) {
// CHECK-X86-64-LABEL: define i32 @_ZN2N06read70
// CHECK-X86-64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-X86-64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-X86-64: %[[shr:.*]] = lshr i64 %[[val]], 56
// CHECK-X86-64: %[[and:.*]] = and i64 %[[shr]], 63
// CHECK-X86-64: %[[trunc:.*]] = trunc i64 %[[and]] to i32
// CHECK-X86-64: ret i32 %[[trunc]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N06read70
// CHECK-PPC64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-PPC64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-PPC64: %[[shr:.*]] = lshr i64 %[[val]], 2
// CHECK-PPC64: %[[and:.*]] = and i64 %[[shr]], 63
// CHECK-PPC64: %[[trunc:.*]] = trunc i64 %[[and]] to i32
// CHECK-PPC64: ret i32 %[[trunc]]
return s->b70;
}
unsigned read71(S* s) {
// CHECK-X86-64-LABEL: define i32 @_ZN2N06read71
// CHECK-X86-64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-X86-64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-X86-64: %[[shr:.*]] = lshr i64 %[[val]], 62
// CHECK-X86-64: %[[trunc:.*]] = trunc i64 %[[shr]] to i32
// CHECK-X86-64: ret i32 %[[trunc]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N06read71
// CHECK-PPC64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i64*
// CHECK-PPC64: %[[val:.*]] = load i64, i64* %[[ptr]]
// CHECK-PPC64: %[[and:.*]] = and i64 %[[val]], 3
// CHECK-PPC64: %[[trunc:.*]] = trunc i64 %[[and]] to i32
// CHECK-PPC64: ret i32 %[[trunc]]
return s->b71;
}
}
namespace N1 {
// Ensure that neither loads nor stores to bitfields are not widened into
// other memory locations. (PR13691)
//
// NOTE: We could potentially widen loads based on their alignment if we are
// comfortable requiring that subsequent memory locations within the
// alignment-widened load are not volatile.
struct S {
char a;
unsigned b : 1;
char c;
};
unsigned read(S* s) {
// CHECK-X86-64-LABEL: define i32 @_ZN2N14read
// CHECK-X86-64: %[[ptr:.*]] = getelementptr inbounds %{{.*}}, %{{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-X86-64: %[[val:.*]] = load i8, i8* %[[ptr]]
// CHECK-X86-64: %[[and:.*]] = and i8 %[[val]], 1
// CHECK-X86-64: %[[ext:.*]] = zext i8 %[[and]] to i32
// CHECK-X86-64: ret i32 %[[ext]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N14read
// CHECK-PPC64: %[[ptr:.*]] = getelementptr inbounds %{{.*}}, %{{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-PPC64: %[[val:.*]] = load i8, i8* %[[ptr]]
// CHECK-PPC64: %[[shr:.*]] = lshr i8 %[[val]], 7
// CHECK-PPC64: %[[ext:.*]] = zext i8 %[[shr]] to i32
// CHECK-PPC64: ret i32 %[[ext]]
return s->b;
}
void write(S* s, unsigned x) {
// CHECK-X86-64-LABEL: define void @_ZN2N15write
// CHECK-X86-64: %[[ptr:.*]] = getelementptr inbounds %{{.*}}, %{{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-X86-64: %[[x_trunc:.*]] = trunc i32 %{{.*}} to i8
// CHECK-X86-64: %[[old:.*]] = load i8, i8* %[[ptr]]
// CHECK-X86-64: %[[x_and:.*]] = and i8 %[[x_trunc]], 1
// CHECK-X86-64: %[[old_and:.*]] = and i8 %[[old]], -2
// CHECK-X86-64: %[[new:.*]] = or i8 %[[old_and]], %[[x_and]]
// CHECK-X86-64: store i8 %[[new]], i8* %[[ptr]]
// CHECK-PPC64-LABEL: define void @_ZN2N15write
// CHECK-PPC64: %[[ptr:.*]] = getelementptr inbounds %{{.*}}, %{{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-PPC64: %[[x_trunc:.*]] = trunc i32 %{{.*}} to i8
// CHECK-PPC64: %[[old:.*]] = load i8, i8* %[[ptr]]
// CHECK-PPC64: %[[x_and:.*]] = and i8 %[[x_trunc]], 1
// CHECK-PPC64: %[[x_shl:.*]] = shl i8 %[[x_and]], 7
// CHECK-PPC64: %[[old_and:.*]] = and i8 %[[old]], 127
// CHECK-PPC64: %[[new:.*]] = or i8 %[[old_and]], %[[x_shl]]
// CHECK-PPC64: store i8 %[[new]], i8* %[[ptr]]
s->b = x;
}
}
namespace N2 {
// Do widen loads and stores to bitfields when those bitfields have padding
// within the struct following them.
struct S {
unsigned b : 24;
void *p;
};
unsigned read(S* s) {
// CHECK-X86-64-LABEL: define i32 @_ZN2N24read
// CHECK-X86-64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i32*
// CHECK-X86-64: %[[val:.*]] = load i32, i32* %[[ptr]]
// CHECK-X86-64: %[[and:.*]] = and i32 %[[val]], 16777215
// CHECK-X86-64: ret i32 %[[and]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N24read
// CHECK-PPC64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i32*
// CHECK-PPC64: %[[val:.*]] = load i32, i32* %[[ptr]]
// CHECK-PPC64: %[[shr:.*]] = lshr i32 %[[val]], 8
// CHECK-PPC64: ret i32 %[[shr]]
return s->b;
}
void write(S* s, unsigned x) {
// CHECK-X86-64-LABEL: define void @_ZN2N25write
// CHECK-X86-64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i32*
// CHECK-X86-64: %[[old:.*]] = load i32, i32* %[[ptr]]
// CHECK-X86-64: %[[x_and:.*]] = and i32 %{{.*}}, 16777215
// CHECK-X86-64: %[[old_and:.*]] = and i32 %[[old]], -16777216
// CHECK-X86-64: %[[new:.*]] = or i32 %[[old_and]], %[[x_and]]
// CHECK-X86-64: store i32 %[[new]], i32* %[[ptr]]
// CHECK-PPC64-LABEL: define void @_ZN2N25write
// CHECK-PPC64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i32*
// CHECK-PPC64: %[[old:.*]] = load i32, i32* %[[ptr]]
// CHECK-PPC64: %[[x_and:.*]] = and i32 %{{.*}}, 16777215
// CHECK-PPC64: %[[x_shl:.*]] = shl i32 %[[x_and]], 8
// CHECK-PPC64: %[[old_and:.*]] = and i32 %[[old]], 255
// CHECK-PPC64: %[[new:.*]] = or i32 %[[old_and]], %[[x_shl]]
// CHECK-PPC64: store i32 %[[new]], i32* %[[ptr]]
s->b = x;
}
}
namespace N3 {
// Do widen loads and stores to bitfields through the trailing padding at the
// end of a struct.
struct S {
unsigned b : 24;
};
unsigned read(S* s) {
// CHECK-X86-64-LABEL: define i32 @_ZN2N34read
// CHECK-X86-64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i32*
// CHECK-X86-64: %[[val:.*]] = load i32, i32* %[[ptr]]
// CHECK-X86-64: %[[and:.*]] = and i32 %[[val]], 16777215
// CHECK-X86-64: ret i32 %[[and]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N34read
// CHECK-PPC64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i32*
// CHECK-PPC64: %[[val:.*]] = load i32, i32* %[[ptr]]
// CHECK-PPC64: %[[shr:.*]] = lshr i32 %[[val]], 8
// CHECK-PPC64: ret i32 %[[shr]]
return s->b;
}
void write(S* s, unsigned x) {
// CHECK-X86-64-LABEL: define void @_ZN2N35write
// CHECK-X86-64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i32*
// CHECK-X86-64: %[[old:.*]] = load i32, i32* %[[ptr]]
// CHECK-X86-64: %[[x_and:.*]] = and i32 %{{.*}}, 16777215
// CHECK-X86-64: %[[old_and:.*]] = and i32 %[[old]], -16777216
// CHECK-X86-64: %[[new:.*]] = or i32 %[[old_and]], %[[x_and]]
// CHECK-X86-64: store i32 %[[new]], i32* %[[ptr]]
// CHECK-PPC64-LABEL: define void @_ZN2N35write
// CHECK-PPC64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i32*
// CHECK-PPC64: %[[old:.*]] = load i32, i32* %[[ptr]]
// CHECK-PPC64: %[[x_and:.*]] = and i32 %{{.*}}, 16777215
// CHECK-PPC64: %[[x_shl:.*]] = shl i32 %[[x_and]], 8
// CHECK-PPC64: %[[old_and:.*]] = and i32 %[[old]], 255
// CHECK-PPC64: %[[new:.*]] = or i32 %[[old_and]], %[[x_shl]]
// CHECK-PPC64: store i32 %[[new]], i32* %[[ptr]]
s->b = x;
}
}
namespace N4 {
// Do NOT widen loads and stores to bitfields into padding at the end of
// a class which might end up with members inside of it when inside a derived
// class.
struct Base {
virtual ~Base() {}
unsigned b : 24;
};
// Imagine some other translation unit introduces:
#if 0
struct Derived : public Base {
char c;
};
#endif
unsigned read(Base* s) {
// FIXME: We should widen this load as long as the function isn't being
// instrumented by ThreadSanitizer.
//
// CHECK-X86-64-LABEL: define i32 @_ZN2N44read
// CHECK-X86-64: %[[gep:.*]] = getelementptr inbounds {{.*}}, {{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-X86-64: %[[ptr:.*]] = bitcast [3 x i8]* %[[gep]] to i24*
// CHECK-X86-64: %[[val:.*]] = load i24, i24* %[[ptr]]
// CHECK-X86-64: %[[ext:.*]] = zext i24 %[[val]] to i32
// CHECK-X86-64: ret i32 %[[ext]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N44read
// CHECK-PPC64: %[[gep:.*]] = getelementptr inbounds {{.*}}, {{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-PPC64: %[[ptr:.*]] = bitcast [3 x i8]* %[[gep]] to i24*
// CHECK-PPC64: %[[val:.*]] = load i24, i24* %[[ptr]]
// CHECK-PPC64: %[[ext:.*]] = zext i24 %[[val]] to i32
// CHECK-PPC64: ret i32 %[[ext]]
return s->b;
}
void write(Base* s, unsigned x) {
// CHECK-X86-64-LABEL: define void @_ZN2N45write
// CHECK-X86-64: %[[gep:.*]] = getelementptr inbounds {{.*}}, {{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-X86-64: %[[ptr:.*]] = bitcast [3 x i8]* %[[gep]] to i24*
// CHECK-X86-64: %[[new:.*]] = trunc i32 %{{.*}} to i24
// CHECK-X86-64: store i24 %[[new]], i24* %[[ptr]]
// CHECK-PPC64-LABEL: define void @_ZN2N45write
// CHECK-PPC64: %[[gep:.*]] = getelementptr inbounds {{.*}}, {{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-PPC64: %[[ptr:.*]] = bitcast [3 x i8]* %[[gep]] to i24*
// CHECK-PPC64: %[[new:.*]] = trunc i32 %{{.*}} to i24
// CHECK-PPC64: store i24 %[[new]], i24* %[[ptr]]
s->b = x;
}
}
namespace N5 {
// Widen through padding at the end of a struct even if that struct
// participates in a union with another struct which has a separate field in
// that location. The reasoning is that if the operation is storing to that
// member of the union, it must be the active member, and thus we can write
// through the padding. If it is a load, it might be a load of a common
// prefix through a non-active member, but in such a case the extra bits
// loaded are masked off anyways.
union U {
struct X { unsigned b : 24; char c; } x;
struct Y { unsigned b : 24; } y;
};
unsigned read(U* u) {
// CHECK-X86-64-LABEL: define i32 @_ZN2N54read
// CHECK-X86-64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i32*
// CHECK-X86-64: %[[val:.*]] = load i32, i32* %[[ptr]]
// CHECK-X86-64: %[[and:.*]] = and i32 %[[val]], 16777215
// CHECK-X86-64: ret i32 %[[and]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N54read
// CHECK-PPC64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i32*
// CHECK-PPC64: %[[val:.*]] = load i32, i32* %[[ptr]]
// CHECK-PPC64: %[[shr:.*]] = lshr i32 %[[val]], 8
// CHECK-PPC64: ret i32 %[[shr]]
return u->y.b;
}
void write(U* u, unsigned x) {
// CHECK-X86-64-LABEL: define void @_ZN2N55write
// CHECK-X86-64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i32*
// CHECK-X86-64: %[[old:.*]] = load i32, i32* %[[ptr]]
// CHECK-X86-64: %[[x_and:.*]] = and i32 %{{.*}}, 16777215
// CHECK-X86-64: %[[old_and:.*]] = and i32 %[[old]], -16777216
// CHECK-X86-64: %[[new:.*]] = or i32 %[[old_and]], %[[x_and]]
// CHECK-X86-64: store i32 %[[new]], i32* %[[ptr]]
// CHECK-PPC64-LABEL: define void @_ZN2N55write
// CHECK-PPC64: %[[ptr:.*]] = bitcast %{{.*}}* %{{.*}} to i32*
// CHECK-PPC64: %[[old:.*]] = load i32, i32* %[[ptr]]
// CHECK-PPC64: %[[x_and:.*]] = and i32 %{{.*}}, 16777215
// CHECK-PPC64: %[[x_shl:.*]] = shl i32 %[[x_and]], 8
// CHECK-PPC64: %[[old_and:.*]] = and i32 %[[old]], 255
// CHECK-PPC64: %[[new:.*]] = or i32 %[[old_and]], %[[x_shl]]
// CHECK-PPC64: store i32 %[[new]], i32* %[[ptr]]
u->y.b = x;
}
}
namespace N6 {
// Zero-length bitfields partition the memory locations of bitfields for the
// purposes of the memory model. That means stores must not span zero-length
// bitfields and loads may only span them when we are not instrumenting with
// ThreadSanitizer.
// FIXME: We currently don't widen loads even without ThreadSanitizer, even
// though we could.
struct S {
unsigned b1 : 24;
unsigned char : 0;
unsigned char b2 : 8;
};
unsigned read(S* s) {
// CHECK-X86-64-LABEL: define i32 @_ZN2N64read
// CHECK-X86-64: %[[ptr1:.*]] = bitcast {{.*}}* %{{.*}} to i24*
// CHECK-X86-64: %[[val1:.*]] = load i24, i24* %[[ptr1]]
// CHECK-X86-64: %[[ext1:.*]] = zext i24 %[[val1]] to i32
// CHECK-X86-64: %[[ptr2:.*]] = getelementptr inbounds {{.*}}, {{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-X86-64: %[[val2:.*]] = load i8, i8* %[[ptr2]]
// CHECK-X86-64: %[[ext2:.*]] = zext i8 %[[val2]] to i32
// CHECK-X86-64: %[[add:.*]] = add nsw i32 %[[ext1]], %[[ext2]]
// CHECK-X86-64: ret i32 %[[add]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N64read
// CHECK-PPC64: %[[ptr1:.*]] = bitcast {{.*}}* %{{.*}} to i24*
// CHECK-PPC64: %[[val1:.*]] = load i24, i24* %[[ptr1]]
// CHECK-PPC64: %[[ext1:.*]] = zext i24 %[[val1]] to i32
// CHECK-PPC64: %[[ptr2:.*]] = getelementptr inbounds {{.*}}, {{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-PPC64: %[[val2:.*]] = load i8, i8* %[[ptr2]]
// CHECK-PPC64: %[[ext2:.*]] = zext i8 %[[val2]] to i32
// CHECK-PPC64: %[[add:.*]] = add nsw i32 %[[ext1]], %[[ext2]]
// CHECK-PPC64: ret i32 %[[add]]
return s->b1 + s->b2;
}
void write(S* s, unsigned x) {
// CHECK-X86-64-LABEL: define void @_ZN2N65write
// CHECK-X86-64: %[[ptr1:.*]] = bitcast {{.*}}* %{{.*}} to i24*
// CHECK-X86-64: %[[new1:.*]] = trunc i32 %{{.*}} to i24
// CHECK-X86-64: store i24 %[[new1]], i24* %[[ptr1]]
// CHECK-X86-64: %[[new2:.*]] = trunc i32 %{{.*}} to i8
// CHECK-X86-64: %[[ptr2:.*]] = getelementptr inbounds {{.*}}, {{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-X86-64: store i8 %[[new2]], i8* %[[ptr2]]
// CHECK-PPC64-LABEL: define void @_ZN2N65write
// CHECK-PPC64: %[[ptr1:.*]] = bitcast {{.*}}* %{{.*}} to i24*
// CHECK-PPC64: %[[new1:.*]] = trunc i32 %{{.*}} to i24
// CHECK-PPC64: store i24 %[[new1]], i24* %[[ptr1]]
// CHECK-PPC64: %[[new2:.*]] = trunc i32 %{{.*}} to i8
// CHECK-PPC64: %[[ptr2:.*]] = getelementptr inbounds {{.*}}, {{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-PPC64: store i8 %[[new2]], i8* %[[ptr2]]
s->b1 = x;
s->b2 = x;
}
}
namespace N7 {
// Similar to N4 except that this adds a virtual base to the picture. (PR18430)
// Do NOT widen loads and stores to bitfields into padding at the end of
// a class which might end up with members inside of it when inside a derived
// class.
struct B1 {
virtual void f();
unsigned b1 : 24;
};
struct B2 : virtual B1 {
virtual ~B2();
unsigned b : 24;
};
// Imagine some other translation unit introduces:
#if 0
struct Derived : public B2 {
char c;
};
#endif
unsigned read(B2* s) {
// FIXME: We should widen this load as long as the function isn't being
// instrumented by ThreadSanitizer.
//
// CHECK-X86-64-LABEL: define i32 @_ZN2N74read
// CHECK-X86-64: %[[gep:.*]] = getelementptr inbounds {{.*}}, {{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-X86-64: %[[ptr:.*]] = bitcast [3 x i8]* %[[gep]] to i24*
// CHECK-X86-64: %[[val:.*]] = load i24, i24* %[[ptr]]
// CHECK-X86-64: %[[ext:.*]] = zext i24 %[[val]] to i32
// CHECK-X86-64: ret i32 %[[ext]]
// CHECK-PPC64-LABEL: define zeroext i32 @_ZN2N74read
// CHECK-PPC64: %[[gep:.*]] = getelementptr inbounds {{.*}}, {{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-PPC64: %[[ptr:.*]] = bitcast [3 x i8]* %[[gep]] to i24*
// CHECK-PPC64: %[[val:.*]] = load i24, i24* %[[ptr]]
// CHECK-PPC64: %[[ext:.*]] = zext i24 %[[val]] to i32
// CHECK-PPC64: ret i32 %[[ext]]
return s->b;
}
void write(B2* s, unsigned x) {
// CHECK-X86-64-LABEL: define void @_ZN2N75write
// CHECK-X86-64: %[[gep:.*]] = getelementptr inbounds {{.*}}, {{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-X86-64: %[[ptr:.*]] = bitcast [3 x i8]* %[[gep]] to i24*
// CHECK-X86-64: %[[new:.*]] = trunc i32 %{{.*}} to i24
// CHECK-X86-64: store i24 %[[new]], i24* %[[ptr]]
// CHECK-PPC64-LABEL: define void @_ZN2N75write
// CHECK-PPC64: %[[gep:.*]] = getelementptr inbounds {{.*}}, {{.*}}* %{{.*}}, i32 0, i32 1
// CHECK-PPC64: %[[ptr:.*]] = bitcast [3 x i8]* %[[gep]] to i24*
// CHECK-PPC64: %[[new:.*]] = trunc i32 %{{.*}} to i24
// CHECK-PPC64: store i24 %[[new]], i24* %[[ptr]]
s->b = x;
}
}