diff options
| -rw-r--r-- | llvm/lib/MC/MCExpr.cpp | 7 | ||||
| -rw-r--r-- | llvm/test/MC/X86/imm-comments.s | 6 |
2 files changed, 8 insertions, 5 deletions
diff --git a/llvm/lib/MC/MCExpr.cpp b/llvm/lib/MC/MCExpr.cpp index 4dfb9719fa7..6f90ff843bd 100644 --- a/llvm/lib/MC/MCExpr.cpp +++ b/llvm/lib/MC/MCExpr.cpp @@ -663,8 +663,10 @@ bool MCExpr::evaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm, /// -(a - b + const) ==> (b - a - const) if (Value.getSymA() && !Value.getSymB()) return false; + + // The cast avoids undefined behavior if the constant is INT64_MIN. Res = MCValue::get(Value.getSymB(), Value.getSymA(), - -Value.getConstant()); + -(uint64_t)Value.getConstant()); break; case MCUnaryExpr::Not: if (!Value.isAbsolute()) @@ -697,9 +699,10 @@ bool MCExpr::evaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm, return false; case MCBinaryExpr::Sub: // Negate RHS and add. + // The cast avoids undefined behavior if the constant is INT64_MIN. return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue, RHSValue.getSymB(), RHSValue.getSymA(), - -RHSValue.getConstant(), Res); + -(uint64_t)RHSValue.getConstant(), Res); case MCBinaryExpr::Add: return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue, diff --git a/llvm/test/MC/X86/imm-comments.s b/llvm/test/MC/X86/imm-comments.s index 7e5324ebf3f..b176d72885b 100644 --- a/llvm/test/MC/X86/imm-comments.s +++ b/llvm/test/MC/X86/imm-comments.s @@ -11,8 +11,8 @@ movl $-2147483648, %eax movabsq $9223372036854775807, %rax -# FIXME: This line causes UB failure. -# movabsq $-9223372036854775808, %rax +# This line should not induce undefined behavior via negation of INT64_MIN. +movabsq $-9223372036854775808, %rax # CHECK: movb $127, %al # CHECK: movb $-128, %al @@ -24,5 +24,5 @@ movabsq $9223372036854775807, %rax # CHECK: movl $-2147483648, %eax # imm = 0xFFFFFFFF80000000 # CHECK: movabsq $9223372036854775807, %rax # imm = 0x7FFFFFFFFFFFFFFF -# FIXME-CHECK: movabsq $-9223372036854775808, %rax # imm = 0x8000000000000000 +# CHECK: movabsq $-9223372036854775808, %rax # imm = 0x8000000000000000 |
