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[PowerPC] Treat 'Z' inline asm constraint as a true memory constraint 

We currently emit incorrect codegen for this constraint because we set it as a
constraint that allows registers. This will cause the value to be copied to the
stack and that address to be passed as the address. This is not what we want.

Fixes: https://bugs.llvm.org/show_bug.cgi?id=42762

Differential revision: https://reviews.llvm.org/D77542
This commit is contained in:
Nemanja Ivanovic 2020-05-22 07:59:12 -05:00
parent 1a493b0fa5
commit aede24ecaa
2 changed files with 15 additions and 1 deletions
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3
clang/lib/Basic/Targets/PPC.h
View File

@ -276,11 +276,12 @@ public:
break;
case 'Q': // Memory operand that is an offset from a register (it is
// usually better to use `m' or `es' in asm statements)
Info.setAllowsRegister();
LLVM_FALLTHROUGH;
case 'Z': // Memory operand that is an indexed or indirect from a
// register (it is usually better to use `m' or `es' in
// asm statements)
Info.setAllowsMemory();
Info.setAllowsRegister();
break;
case 'R': // AIX TOC entry
case 'a': // Address operand that is an indexed or indirect from a

13
clang/test/CodeGen/ppc64-inline-asm.c
View File

@ -37,3 +37,16 @@ double test_fmax(double x, double y) {
// CHECK-LABEL: double @test_fmax(double %x, double %y)
// CHECK: call double asm "xsmaxdp ${0:x}, ${1:x}, ${2:x}", "=^ws,^ws,^ws"(double %x, double %y)
}
void testZ(void *addr) {
asm volatile ("dcbz %y0\n" :: "Z"(*(unsigned char *)addr) : "memory");
// CHECK-LABEL: void @testZ(i8* %addr)
// CHECK: call void asm sideeffect "dcbz ${0:y}\0A", "*Z,~{memory}"(i8* %addr)
}
void testZwOff(void *addr, long long off) {
asm volatile ("dcbz %y0\n" :: "Z"(*(unsigned char *)(addr + off)) : "memory");
// CHECK-LABEL: void @testZwOff(i8* %addr, i64 %off)
// CHECK: %[[VAL:[^ ]+]] = getelementptr i8, i8* %addr, i64 %off
// CHECK: call void asm sideeffect "dcbz ${0:y}\0A", "*Z,~{memory}"(i8* %[[VAL]])
}