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llvm-project/llvm/test/CodeGen/X86/fold-add.ll
Fangrui Song 570871eab5
[X86] Don't convert local function foo in the same section to foo(%rip) when the offset is near INT32_MIN 
```
define internal void @foo() {
  ret void
}
define i64 @main() {
  ret i64 add (i64 ptrtoint (ptr @foo to i64), i64 -2147483626)
}
```

When `foo` is a local symbol, `foo` and `main` are in the same section,
and `offset` is near INT32_MIN, referencing `foo+offset` in `main` with
RIP-relative addressing needs `leaq .text+offset1(%rip), %rax` where
`offset1 < offset`, and `offset1` might underflow.
(https://discourse.llvm.org/t/arithmetic-referencing-dso-local-function-causes-compilation-error-on-linux-x64/80033):

Don't use RIP-relative addressing if the negative offset is near
INT32_MIN. Arbitrarily reuse the magic number in isOffsetSuitableForCodeModel to
guard against the edge case when `address(current_instruction)-foo < 4GiB-16MiB`.
If the difference is larger than 4GiB-16MiB, `ret i64 add (i64 ptrtoint
(ptr @foo to i64), i64 -2**32+256MiB)` would still cause the assembly
issue, such cases are unrealistic.

Pull Request: https://github.com/llvm/llvm-project/pull/98438
2024-09-30 22:46:08 -07:00

251 lines
7.1 KiB
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; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -mtriple=x86_64 -relocation-model=static < %s | FileCheck --check-prefixes=STATIC %s
; RUN: llc -mtriple=x86_64 -relocation-model=pic < %s | FileCheck --check-prefixes=PIC %s
; RUN: llc -mtriple=x86_64 -code-model=medium -relocation-model=static < %s | FileCheck --check-prefixes=MSTATIC %s
; RUN: llc -mtriple=x86_64 -code-model=medium -relocation-model=pic < %s | FileCheck --check-prefixes=MPIC %s
@foo = internal global i32 0
define dso_local i64 @zero() #0 {
; STATIC-LABEL: zero:
; STATIC: # %bb.0: # %entry
; STATIC-NEXT: movl $foo, %eax
; STATIC-NEXT: retq
;
; PIC-LABEL: zero:
; PIC: # %bb.0: # %entry
; PIC-NEXT: leaq foo(%rip), %rax
; PIC-NEXT: retq
;
; MSTATIC-LABEL: zero:
; MSTATIC: # %bb.0: # %entry
; MSTATIC-NEXT: movabsq $foo, %rax
; MSTATIC-NEXT: retq
;
; MPIC-LABEL: zero:
; MPIC: # %bb.0: # %entry
; MPIC-NEXT: leaq _GLOBAL_OFFSET_TABLE_(%rip), %rcx
; MPIC-NEXT: movabsq $foo@GOTOFF, %rax
; MPIC-NEXT: addq %rcx, %rax
; MPIC-NEXT: retq
entry:
ret i64 add (i64 ptrtoint (ptr @foo to i64), i64 0)
}
define dso_local i64 @one() #0 {
; STATIC-LABEL: one:
; STATIC: # %bb.0: # %entry
; STATIC-NEXT: movl $foo+1, %eax
; STATIC-NEXT: retq
;
; PIC-LABEL: one:
; PIC: # %bb.0: # %entry
; PIC-NEXT: leaq foo+1(%rip), %rax
; PIC-NEXT: retq
;
; MSTATIC-LABEL: one:
; MSTATIC: # %bb.0: # %entry
; MSTATIC-NEXT: movabsq $foo+1, %rax
; MSTATIC-NEXT: retq
;
; MPIC-LABEL: one:
; MPIC: # %bb.0: # %entry
; MPIC-NEXT: leaq _GLOBAL_OFFSET_TABLE_(%rip), %rax
; MPIC-NEXT: movabsq $foo@GOTOFF, %rcx
; MPIC-NEXT: leaq 1(%rax,%rcx), %rax
; MPIC-NEXT: retq
entry:
ret i64 add (i64 ptrtoint (ptr @foo to i64), i64 1)
}
;; Check we don't fold a large offset into leaq, otherwise
;; the large r_addend can easily cause a relocation overflow.
define dso_local i64 @large() #0 {
; STATIC-LABEL: large:
; STATIC: # %bb.0: # %entry
; STATIC-NEXT: movl $1701208431, %eax # imm = 0x6566616F
; STATIC-NEXT: leaq foo(%rax), %rax
; STATIC-NEXT: retq
;
; PIC-LABEL: large:
; PIC: # %bb.0: # %entry
; PIC-NEXT: leaq foo(%rip), %rax
; PIC-NEXT: addq $1701208431, %rax # imm = 0x6566616F
; PIC-NEXT: retq
;
; MSTATIC-LABEL: large:
; MSTATIC: # %bb.0: # %entry
; MSTATIC-NEXT: movabsq $foo, %rax
; MSTATIC-NEXT: addq $1701208431, %rax # imm = 0x6566616F
; MSTATIC-NEXT: retq
;
; MPIC-LABEL: large:
; MPIC: # %bb.0: # %entry
; MPIC-NEXT: leaq _GLOBAL_OFFSET_TABLE_(%rip), %rax
; MPIC-NEXT: movabsq $foo@GOTOFF, %rcx
; MPIC-NEXT: leaq 1701208431(%rax,%rcx), %rax
; MPIC-NEXT: retq
entry:
ret i64 add (i64 ptrtoint (ptr @foo to i64), i64 1701208431)
}
;; Test we don't emit movl foo-1, %eax. ELF R_X86_64_32 does not allow
;; a negative value.
define dso_local i64 @neg_1() #0 {
; STATIC-LABEL: neg_1:
; STATIC: # %bb.0: # %entry
; STATIC-NEXT: leaq foo-1(%rip), %rax
; STATIC-NEXT: retq
;
; PIC-LABEL: neg_1:
; PIC: # %bb.0: # %entry
; PIC-NEXT: leaq foo-1(%rip), %rax
; PIC-NEXT: retq
;
; MSTATIC-LABEL: neg_1:
; MSTATIC: # %bb.0: # %entry
; MSTATIC-NEXT: movabsq $foo, %rax
; MSTATIC-NEXT: decq %rax
; MSTATIC-NEXT: retq
;
; MPIC-LABEL: neg_1:
; MPIC: # %bb.0: # %entry
; MPIC-NEXT: leaq _GLOBAL_OFFSET_TABLE_(%rip), %rax
; MPIC-NEXT: movabsq $foo@GOTOFF, %rcx
; MPIC-NEXT: leaq -1(%rax,%rcx), %rax
; MPIC-NEXT: retq
entry:
ret i64 add (i64 ptrtoint (ptr @foo to i64), i64 -1)
}
;; Test we don't emit movl foo-2147483648, %eax. ELF R_X86_64_32 does not allow
;; a negative value.
define dso_local i64 @neg_0x80000000() #0 {
; STATIC-LABEL: neg_0x80000000:
; STATIC: # %bb.0: # %entry
; STATIC-NEXT: leaq foo-2147483648(%rip), %rax
; STATIC-NEXT: retq
;
; PIC-LABEL: neg_0x80000000:
; PIC: # %bb.0: # %entry
; PIC-NEXT: leaq foo-2147483648(%rip), %rax
; PIC-NEXT: retq
;
; MSTATIC-LABEL: neg_0x80000000:
; MSTATIC: # %bb.0: # %entry
; MSTATIC-NEXT: movabsq $foo, %rax
; MSTATIC-NEXT: addq $-2147483648, %rax # imm = 0x80000000
; MSTATIC-NEXT: retq
;
; MPIC-LABEL: neg_0x80000000:
; MPIC: # %bb.0: # %entry
; MPIC-NEXT: leaq _GLOBAL_OFFSET_TABLE_(%rip), %rax
; MPIC-NEXT: movabsq $foo@GOTOFF, %rcx
; MPIC-NEXT: leaq -2147483648(%rax,%rcx), %rax
; MPIC-NEXT: retq
entry:
ret i64 add (i64 ptrtoint (ptr @foo to i64), i64 -2147483648)
}
define dso_local i64 @neg_0x80000001() #0 {
; STATIC-LABEL: neg_0x80000001:
; STATIC: # %bb.0: # %entry
; STATIC-NEXT: movabsq $-2147483649, %rax # imm = 0xFFFFFFFF7FFFFFFF
; STATIC-NEXT: leaq foo(%rax), %rax
; STATIC-NEXT: retq
;
; PIC-LABEL: neg_0x80000001:
; PIC: # %bb.0: # %entry
; PIC-NEXT: leaq foo(%rip), %rcx
; PIC-NEXT: movabsq $-2147483649, %rax # imm = 0xFFFFFFFF7FFFFFFF
; PIC-NEXT: addq %rcx, %rax
; PIC-NEXT: retq
;
; MSTATIC-LABEL: neg_0x80000001:
; MSTATIC: # %bb.0: # %entry
; MSTATIC-NEXT: movabsq $-2147483649, %rcx # imm = 0xFFFFFFFF7FFFFFFF
; MSTATIC-NEXT: movabsq $foo, %rax
; MSTATIC-NEXT: addq %rcx, %rax
; MSTATIC-NEXT: retq
;
; MPIC-LABEL: neg_0x80000001:
; MPIC: # %bb.0: # %entry
; MPIC-NEXT: leaq _GLOBAL_OFFSET_TABLE_(%rip), %rax
; MPIC-NEXT: movabsq $foo@GOTOFF, %rcx
; MPIC-NEXT: addq %rax, %rcx
; MPIC-NEXT: movabsq $-2147483649, %rax # imm = 0xFFFFFFFF7FFFFFFF
; MPIC-NEXT: addq %rcx, %rax
; MPIC-NEXT: retq
entry:
ret i64 add (i64 ptrtoint (ptr @foo to i64), i64 -2147483649)
}
define internal void @bar() #0 {
; STATIC-LABEL: bar:
; STATIC: # %bb.0:
; STATIC-NEXT: retq
;
; PIC-LABEL: bar:
; PIC: # %bb.0:
; PIC-NEXT: retq
;
; MSTATIC-LABEL: bar:
; MSTATIC: # %bb.0:
; MSTATIC-NEXT: retq
;
; MPIC-LABEL: bar:
; MPIC: # %bb.0:
; MPIC-NEXT: retq
ret void
}
define dso_local i64 @fun_neg_0xfeffffff() #0 {
; STATIC-LABEL: fun_neg_0xfeffffff:
; STATIC: # %bb.0:
; STATIC-NEXT: movl $bar, %eax
; STATIC-NEXT: addq $-16777217, %rax # imm = 0xFEFFFFFF
; STATIC-NEXT: retq
;
; PIC-LABEL: fun_neg_0xfeffffff:
; PIC: # %bb.0:
; PIC-NEXT: leaq bar-16777217(%rip), %rax
; PIC-NEXT: retq
;
; MSTATIC-LABEL: fun_neg_0xfeffffff:
; MSTATIC: # %bb.0:
; MSTATIC-NEXT: movl $bar, %eax
; MSTATIC-NEXT: addq $-16777217, %rax # imm = 0xFEFFFFFF
; MSTATIC-NEXT: retq
;
; MPIC-LABEL: fun_neg_0xfeffffff:
; MPIC: # %bb.0:
; MPIC-NEXT: leaq bar-16777217(%rip), %rax
; MPIC-NEXT: retq
ret i64 add (i64 ptrtoint (ptr @bar to i64), i64 -16777217)
}
define dso_local i64 @fun_neg_ff000000() #0 {
; STATIC-LABEL: fun_neg_ff000000:
; STATIC: # %bb.0:
; STATIC-NEXT: leaq bar-16777216(%rip), %rax
; STATIC-NEXT: retq
;
; PIC-LABEL: fun_neg_ff000000:
; PIC: # %bb.0:
; PIC-NEXT: leaq bar-16777216(%rip), %rax
; PIC-NEXT: retq
;
; MSTATIC-LABEL: fun_neg_ff000000:
; MSTATIC: # %bb.0:
; MSTATIC-NEXT: leaq bar-16777216(%rip), %rax
; MSTATIC-NEXT: retq
;
; MPIC-LABEL: fun_neg_ff000000:
; MPIC: # %bb.0:
; MPIC-NEXT: leaq bar-16777216(%rip), %rax
; MPIC-NEXT: retq
ret i64 add (i64 ptrtoint (ptr @bar to i64), i64 -16777216)
}
attributes #0 = { nounwind }
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