MC: Centralize X86 PC-relative fixup adjustment in MCAssembler

Move the X86 PC-relative fixup adjustment from
X86MCCodeEmitter::emitImmediate to MCAssembler, leveraging a generalized
evaluateFixup. This saves a MCBinaryExpr. For `call foo`, the fixup
expression is now `foo` instead of `foo-4`. There is no change in
generated relocations.

In bolt/lib/Target/X86/X86MCPlusBuilder.cpp, createRelocation needs to
decrease the addend.

Both max-rss and instructions:u show a minor decrease.
https://llvm-compile-time-tracker.com/compare.php?from=ea600576a6f94d6f28925c4b99962cc26b463c29&to=016e8fd4ddf851e5555f606c6394241d68f1a7bb&stat=max-rss&linkStats=on

Next: Update targets that use FKF_IsAlignedDownTo32Bits to define
`evaluateFixup` and remove FKF_IsAlignedDownTo32Bits from the generic
code.

Pull Request: #147113

Author: MaskRay

bolt/lib/Target/X86/X86MCPlusBuilder.cpp

@@ -2441,6 +2441,7 @@ class X86MCPlusBuilder : public MCPlusBuilder {
 
     assert(FKI.TargetOffset == 0 && "0-bit relocation offset expected");
     const uint64_t RelOffset = Fixup.getOffset();
+    auto [RelSymbol, RelAddend] = extractFixupExpr(Fixup);
 
     uint32_t RelType;
     if (Fixup.isPCRel()) {
@@ -2452,6 +2453,9 @@ class X86MCPlusBuilder : public MCPlusBuilder {
       case 32: RelType = ELF::R_X86_64_PC32; break;
       case 64: RelType = ELF::R_X86_64_PC64; break;
       }
+      // Adjust PC-relative fixup offsets, which are calculated from the start
+      // of the next instruction.
+      RelAddend -= FKI.TargetSize / 8;
     } else {
       switch (FKI.TargetSize) {
       default:
@@ -2463,8 +2467,6 @@ class X86MCPlusBuilder : public MCPlusBuilder {
       }
     }
 
-    auto [RelSymbol, RelAddend] = extractFixupExpr(Fixup);
-
     return Relocation({RelOffset, RelSymbol, RelType, RelAddend, 0});
   }
 

llvm/include/llvm/MC/MCValue.h

@@ -42,6 +42,7 @@ class MCValue {
   friend class MCExpr;
   MCValue() = default;
   int64_t getConstant() const { return Cst; }
+  void setConstant(int64_t C) { Cst = C; }
   uint32_t getSpecifier() const { return Specifier; }
   void setSpecifier(uint32_t S) { Specifier = S; }
 

llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp

@@ -168,8 +168,8 @@ class X86AsmBackend : public MCAsmBackend {
 
   MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override;
 
-  bool shouldForceRelocation(const MCFixup &, const MCValue &);
-
+  std::optional<bool> evaluateFixup(const MCFragment &, MCFixup &, MCValue &,
+                                    uint64_t &) override;
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
                   MutableArrayRef<char> Data, uint64_t Value,
                   bool IsResolved) override;
@@ -678,6 +678,37 @@ static unsigned getFixupKindSize(unsigned Kind) {
   }
 }
 
+constexpr char GotSymName[] = "_GLOBAL_OFFSET_TABLE_";
+
+// Adjust PC-relative fixup offsets, which are calculated from the start of the
+// next instruction.
+std::optional<bool> X86AsmBackend::evaluateFixup(const MCFragment &,
+                                                 MCFixup &Fixup,
+                                                 MCValue &Target, uint64_t &) {
+  if (Fixup.isPCRel()) {
+    switch (Fixup.getTargetKind()) {
+    case FK_Data_1:
+      Target.setConstant(Target.getConstant() - 1);
+      break;
+    case FK_Data_2:
+      Target.setConstant(Target.getConstant() - 2);
+      break;
+    default: {
+      Target.setConstant(Target.getConstant() - 4);
+      auto *Add = Target.getAddSym();
+      // If this is a pc-relative load off _GLOBAL_OFFSET_TABLE_:
+      // leaq _GLOBAL_OFFSET_TABLE_(%rip), %r15
+      // this needs to be a GOTPC32 relocation.
+      if (Add && Add->getName() == GotSymName)
+        Fixup = MCFixup::create(Fixup.getOffset(), Fixup.getValue(),
+                                X86::reloc_global_offset_table);
+    } break;
+    }
+  }
+  // Use default handling for `Value` and `IsResolved`.
+  return {};
+}
+
 void X86AsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
                                const MCValue &Target,
                                MutableArrayRef<char> Data, uint64_t Value,

llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp

@@ -470,6 +470,9 @@ enum GlobalOffsetTableExprKind { GOT_None, GOT_Normal, GOT_SymDiff };
 /// ELF i386 as _GLOBAL_OFFSET_TABLE_ is magical. We check only simple case that
 /// are know to be used: _GLOBAL_OFFSET_TABLE_ by itself or at the start of a
 /// binary expression.
+///
+/// TODO: Move this to X86AsmBackend.cpp at relocation decision phase so that we
+/// don't have to mess with MCExpr.
 static GlobalOffsetTableExprKind
 startsWithGlobalOffsetTable(const MCExpr *Expr) {
   const MCExpr *RHS = nullptr;
@@ -587,22 +590,11 @@ void X86MCCodeEmitter::emitImmediate(const MCOperand &DispOp, SMLoc Loc,
     }
   }
 
-  // If the fixup is pc-relative, we need to bias the value to be relative to
-  // the start of the field, not the end of the field.
-  if (PCRel) {
-    ImmOffset -= Size;
-    // If this is a pc-relative load off _GLOBAL_OFFSET_TABLE_:
-    // leaq _GLOBAL_OFFSET_TABLE_(%rip), %r15
-    // this needs to be a GOTPC32 relocation.
-    if (Size == 4 && startsWithGlobalOffsetTable(Expr) != GOT_None)
-      FixupKind = X86::reloc_global_offset_table;
-  }
-
   if (ImmOffset)
     Expr = MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(ImmOffset, Ctx),
                                    Ctx, Expr->getLoc());
 
-  // Emit a symbolic constant as a fixup and 4 zeros.
+  // Emit a symbolic constant as a fixup and a few zero bytes.
   Fixups.push_back(MCFixup::create(static_cast<uint32_t>(CB.size() - StartByte),
                                    Expr, FixupKind, PCRel));
   emitConstant(0, Size, CB);

llvm/test/CodeGen/X86/AMX/amx-lower-tile-copy.ll

@@ -87,7 +87,7 @@ define dso_local void @test1(ptr%buf) nounwind {
 ; EGPR-NEXT:    xorl %eax, %eax # encoding: [0x31,0xc0]
 ; EGPR-NEXT:    testb %al, %al # encoding: [0x84,0xc0]
 ; EGPR-NEXT:    jne .LBB0_3 # encoding: [0x75,A]
-; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB0_3-1, kind: FK_PCRel_1
+; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB0_3, kind: FK_PCRel_1
 ; EGPR-NEXT:  # %bb.1: # %loop.header.preheader
 ; EGPR-NEXT:    movq %rdi, %rbx # encoding: [0x48,0x89,0xfb]
 ; EGPR-NEXT:    xorl %r14d, %r14d # encoding: [0x45,0x31,0xf6]
@@ -100,7 +100,7 @@ define dso_local void @test1(ptr%buf) nounwind {
 ; EGPR-NEXT:    # EVEX TO VEX Compression encoding: [0xc4,0xe2,0x7a,0x4b,0x9c,0x04,0xd0,0x0b,0x00,0x00]
 ; EGPR-NEXT:    vzeroupper # encoding: [0xc5,0xf8,0x77]
 ; EGPR-NEXT:    callq foo # encoding: [0xe8,A,A,A,A]
-; EGPR-NEXT:    # fixup A - offset: 1, value: foo-4, kind: reloc_branch_4byte_pcrel
+; EGPR-NEXT:    # fixup A - offset: 1, value: foo, kind: reloc_branch_4byte_pcrel
 ; EGPR-NEXT:    ldtilecfg {{[0-9]+}}(%rsp) # EVEX TO VEX Compression encoding: [0xc4,0xe2,0x78,0x49,0x84,0x24,0xc0,0x03,0x00,0x00]
 ; EGPR-NEXT:    movabsq $64, %rax # encoding: [0x48,0xb8,0x40,0x00,0x00,0x00,0x00,0x00,0x00,0x00]
 ; EGPR-NEXT:    tileloadd 3024(%rsp,%rax), %tmm3 # 1024-byte Folded Reload
@@ -116,7 +116,7 @@ define dso_local void @test1(ptr%buf) nounwind {
 ; EGPR-NEXT:    incl %r14d # encoding: [0x41,0xff,0xc6]
 ; EGPR-NEXT:    cmpw $100, %r14w # encoding: [0x66,0x41,0x83,0xfe,0x64]
 ; EGPR-NEXT:    jl .LBB0_2 # encoding: [0x7c,A]
-; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB0_2-1, kind: FK_PCRel_1
+; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB0_2, kind: FK_PCRel_1
 ; EGPR-NEXT:  .LBB0_3: # %exit
 ; EGPR-NEXT:    addq $4056, %rsp # encoding: [0x48,0x81,0xc4,0xd8,0x0f,0x00,0x00]
 ; EGPR-NEXT:    # imm = 0xFD8
@@ -226,7 +226,7 @@ define dso_local void @test2(ptr%buf) nounwind {
 ; EGPR-NEXT:    xorl %eax, %eax # encoding: [0x31,0xc0]
 ; EGPR-NEXT:    testb %al, %al # encoding: [0x84,0xc0]
 ; EGPR-NEXT:    jne .LBB1_3 # encoding: [0x75,A]
-; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB1_3-1, kind: FK_PCRel_1
+; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB1_3, kind: FK_PCRel_1
 ; EGPR-NEXT:  # %bb.1: # %loop.header.preheader
 ; EGPR-NEXT:    movq %rdi, %rbx # encoding: [0x48,0x89,0xfb]
 ; EGPR-NEXT:    xorl %r14d, %r14d # encoding: [0x45,0x31,0xf6]
@@ -237,7 +237,7 @@ define dso_local void @test2(ptr%buf) nounwind {
 ; EGPR-NEXT:    tilezero %tmm0 # encoding: [0xc4,0xe2,0x7b,0x49,0xc0]
 ; EGPR-NEXT:    vzeroupper # encoding: [0xc5,0xf8,0x77]
 ; EGPR-NEXT:    callq foo # encoding: [0xe8,A,A,A,A]
-; EGPR-NEXT:    # fixup A - offset: 1, value: foo-4, kind: reloc_branch_4byte_pcrel
+; EGPR-NEXT:    # fixup A - offset: 1, value: foo, kind: reloc_branch_4byte_pcrel
 ; EGPR-NEXT:    ldtilecfg {{[0-9]+}}(%rsp) # EVEX TO VEX Compression encoding: [0xc4,0xe2,0x78,0x49,0x44,0x24,0x08]
 ; EGPR-NEXT:    tilezero %tmm2 # encoding: [0xc4,0xe2,0x7b,0x49,0xd0]
 ; EGPR-NEXT:    tileloadd (%rbx,%r15), %tmm0 # EVEX TO VEX Compression encoding: [0xc4,0xa2,0x7b,0x4b,0x04,0x3b]
@@ -247,7 +247,7 @@ define dso_local void @test2(ptr%buf) nounwind {
 ; EGPR-NEXT:    incl %r14d # encoding: [0x41,0xff,0xc6]
 ; EGPR-NEXT:    cmpw $100, %r14w # encoding: [0x66,0x41,0x83,0xfe,0x64]
 ; EGPR-NEXT:    jl .LBB1_2 # encoding: [0x7c,A]
-; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB1_2-1, kind: FK_PCRel_1
+; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB1_2, kind: FK_PCRel_1
 ; EGPR-NEXT:  .LBB1_3: # %exit
 ; EGPR-NEXT:    addq $72, %rsp # encoding: [0x48,0x83,0xc4,0x48]
 ; EGPR-NEXT:    popq %rbx # encoding: [0x5b]

llvm/test/CodeGen/X86/AMX/amx-spill-merge.ll

@@ -125,7 +125,7 @@ define dso_local void @test_api(i16 signext %0, i16 signext %1) nounwind {
 ; EGPR-NEXT:    xorl %eax, %eax # encoding: [0x31,0xc0]
 ; EGPR-NEXT:    testb %al, %al # encoding: [0x84,0xc0]
 ; EGPR-NEXT:    jne .LBB0_2 # encoding: [0x75,A]
-; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB0_2-1, kind: FK_PCRel_1
+; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB0_2, kind: FK_PCRel_1
 ; EGPR-NEXT:  # %bb.1: # %if.true
 ; EGPR-NEXT:    movl $buf, %eax # encoding: [0xb8,A,A,A,A]
 ; EGPR-NEXT:    # fixup A - offset: 1, value: buf, kind: FK_Data_4
@@ -143,13 +143,13 @@ define dso_local void @test_api(i16 signext %0, i16 signext %1) nounwind {
 ; EGPR-NEXT:    xorl %eax, %eax # encoding: [0x31,0xc0]
 ; EGPR-NEXT:    vzeroupper # encoding: [0xc5,0xf8,0x77]
 ; EGPR-NEXT:    callq foo # encoding: [0xe8,A,A,A,A]
-; EGPR-NEXT:    # fixup A - offset: 1, value: foo-4, kind: reloc_branch_4byte_pcrel
+; EGPR-NEXT:    # fixup A - offset: 1, value: foo, kind: reloc_branch_4byte_pcrel
 ; EGPR-NEXT:    ldtilecfg (%rsp) # EVEX TO VEX Compression encoding: [0xc4,0xe2,0x78,0x49,0x04,0x24]
 ; EGPR-NEXT:    movabsq $64, %rax # encoding: [0x48,0xb8,0x40,0x00,0x00,0x00,0x00,0x00,0x00,0x00]
 ; EGPR-NEXT:    tileloadd 64(%rsp,%rax), %tmm6 # 1024-byte Folded Reload
 ; EGPR-NEXT:    # EVEX TO VEX Compression encoding: [0xc4,0xe2,0x7b,0x4b,0x74,0x04,0x40]
 ; EGPR-NEXT:    jmp .LBB0_3 # encoding: [0xeb,A]
-; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB0_3-1, kind: FK_PCRel_1
+; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB0_3, kind: FK_PCRel_1
 ; EGPR-NEXT:  .LBB0_2: # %if.false
 ; EGPR-NEXT:    movl $buf, %eax # encoding: [0xb8,A,A,A,A]
 ; EGPR-NEXT:    # fixup A - offset: 1, value: buf, kind: FK_Data_4
@@ -167,7 +167,7 @@ define dso_local void @test_api(i16 signext %0, i16 signext %1) nounwind {
 ; EGPR-NEXT:    xorl %eax, %eax # encoding: [0x31,0xc0]
 ; EGPR-NEXT:    vzeroupper # encoding: [0xc5,0xf8,0x77]
 ; EGPR-NEXT:    callq foo # encoding: [0xe8,A,A,A,A]
-; EGPR-NEXT:    # fixup A - offset: 1, value: foo-4, kind: reloc_branch_4byte_pcrel
+; EGPR-NEXT:    # fixup A - offset: 1, value: foo, kind: reloc_branch_4byte_pcrel
 ; EGPR-NEXT:    ldtilecfg (%rsp) # EVEX TO VEX Compression encoding: [0xc4,0xe2,0x78,0x49,0x04,0x24]
 ; EGPR-NEXT:    movabsq $64, %rax # encoding: [0x48,0xb8,0x40,0x00,0x00,0x00,0x00,0x00,0x00,0x00]
 ; EGPR-NEXT:    tileloadd 64(%rsp,%rax), %tmm6 # 1024-byte Folded Reload
@@ -294,7 +294,7 @@ define dso_local void @test3(ptr%buf) nounwind {
 ; EGPR-NEXT:    xorl %eax, %eax # encoding: [0x31,0xc0]
 ; EGPR-NEXT:    testb %al, %al # encoding: [0x84,0xc0]
 ; EGPR-NEXT:    jne .LBB1_3 # encoding: [0x75,A]
-; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB1_3-1, kind: FK_PCRel_1
+; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB1_3, kind: FK_PCRel_1
 ; EGPR-NEXT:  # %bb.1: # %loop.header.preheader
 ; EGPR-NEXT:    movq %rdi, %rbx # encoding: [0x48,0x89,0xfb]
 ; EGPR-NEXT:    movl $32, %r14d # encoding: [0x41,0xbe,0x20,0x00,0x00,0x00]
@@ -307,7 +307,7 @@ define dso_local void @test3(ptr%buf) nounwind {
 ; EGPR-NEXT:    tilezero %tmm0 # encoding: [0xc4,0xe2,0x7b,0x49,0xc0]
 ; EGPR-NEXT:    vzeroupper # encoding: [0xc5,0xf8,0x77]
 ; EGPR-NEXT:    callq foo # encoding: [0xe8,A,A,A,A]
-; EGPR-NEXT:    # fixup A - offset: 1, value: foo-4, kind: reloc_branch_4byte_pcrel
+; EGPR-NEXT:    # fixup A - offset: 1, value: foo, kind: reloc_branch_4byte_pcrel
 ; EGPR-NEXT:    ldtilecfg {{[0-9]+}}(%rsp) # EVEX TO VEX Compression encoding: [0xc4,0xe2,0x78,0x49,0x44,0x24,0x08]
 ; EGPR-NEXT:    tilezero %tmm0 # encoding: [0xc4,0xe2,0x7b,0x49,0xc0]
 ; EGPR-NEXT:    tileloadd (%rbx,%r14), %tmm1 # EVEX TO VEX Compression encoding: [0xc4,0xa2,0x7b,0x4b,0x0c,0x33]
@@ -318,7 +318,7 @@ define dso_local void @test3(ptr%buf) nounwind {
 ; EGPR-NEXT:    incl %r15d # encoding: [0x41,0xff,0xc7]
 ; EGPR-NEXT:    cmpw $100, %r15w # encoding: [0x66,0x41,0x83,0xff,0x64]
 ; EGPR-NEXT:    jl .LBB1_2 # encoding: [0x7c,A]
-; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB1_2-1, kind: FK_PCRel_1
+; EGPR-NEXT:    # fixup A - offset: 1, value: .LBB1_2, kind: FK_PCRel_1
 ; EGPR-NEXT:  .LBB1_3: # %exit
 ; EGPR-NEXT:    addq $72, %rsp # encoding: [0x48,0x83,0xc4,0x48]
 ; EGPR-NEXT:    popq %rbx # encoding: [0x5b]

llvm/test/CodeGen/X86/absolute-cmp.ll

@@ -16,12 +16,12 @@ define void @foo8(i64 %val) {
 ; NOPIC-NEXT:    cmpq $cmp8@ABS8, %rdi # encoding: [0x48,0x83,0xff,A]
 ; NOPIC-NEXT:    # fixup A - offset: 3, value: cmp8@ABS8, kind: FK_Data_1
 ; NOPIC-NEXT:    ja .LBB0_2 # encoding: [0x77,A]
-; NOPIC-NEXT:    # fixup A - offset: 1, value: .LBB0_2-1, kind: FK_PCRel_1
+; NOPIC-NEXT:    # fixup A - offset: 1, value: .LBB0_2, kind: FK_PCRel_1
 ; NOPIC-NEXT:  # %bb.1: # %t
 ; NOPIC-NEXT:    pushq %rax # encoding: [0x50]
 ; NOPIC-NEXT:    .cfi_def_cfa_offset 16
 ; NOPIC-NEXT:    callq f@PLT # encoding: [0xe8,A,A,A,A]
-; NOPIC-NEXT:    # fixup A - offset: 1, value: f@PLT-4, kind: FK_PCRel_4
+; NOPIC-NEXT:    # fixup A - offset: 1, value: f@PLT, kind: FK_PCRel_4
 ; NOPIC-NEXT:    popq %rax # encoding: [0x58]
 ; NOPIC-NEXT:    .cfi_def_cfa_offset 8
 ; NOPIC-NEXT:  .LBB0_2: # %f
@@ -32,12 +32,12 @@ define void @foo8(i64 %val) {
 ; PIC-NEXT:    cmpq $cmp8@ABS8, %rdi # encoding: [0x48,0x83,0xff,A]
 ; PIC-NEXT:    # fixup A - offset: 3, value: cmp8@ABS8, kind: FK_Data_1
 ; PIC-NEXT:    ja .LBB0_2 # encoding: [0x77,A]
-; PIC-NEXT:    # fixup A - offset: 1, value: .LBB0_2-1, kind: FK_PCRel_1
+; PIC-NEXT:    # fixup A - offset: 1, value: .LBB0_2, kind: FK_PCRel_1
 ; PIC-NEXT:  # %bb.1: # %t
 ; PIC-NEXT:    pushq %rax # encoding: [0x50]
 ; PIC-NEXT:    .cfi_def_cfa_offset 16
 ; PIC-NEXT:    callq f@PLT # encoding: [0xe8,A,A,A,A]
-; PIC-NEXT:    # fixup A - offset: 1, value: f@PLT-4, kind: FK_PCRel_4
+; PIC-NEXT:    # fixup A - offset: 1, value: f@PLT, kind: FK_PCRel_4
 ; PIC-NEXT:    popq %rax # encoding: [0x58]
 ; PIC-NEXT:    .cfi_def_cfa_offset 8
 ; PIC-NEXT:  .LBB0_2: # %f
@@ -59,12 +59,12 @@ define void @foo32(i64 %val) {
 ; NOPIC-NEXT:    cmpq $cmp32, %rdi # encoding: [0x48,0x81,0xff,A,A,A,A]
 ; NOPIC-NEXT:    # fixup A - offset: 3, value: cmp32, kind: reloc_signed_4byte
 ; NOPIC-NEXT:    ja .LBB1_2 # encoding: [0x77,A]
-; NOPIC-NEXT:    # fixup A - offset: 1, value: .LBB1_2-1, kind: FK_PCRel_1
+; NOPIC-NEXT:    # fixup A - offset: 1, value: .LBB1_2, kind: FK_PCRel_1
 ; NOPIC-NEXT:  # %bb.1: # %t
 ; NOPIC-NEXT:    pushq %rax # encoding: [0x50]
 ; NOPIC-NEXT:    .cfi_def_cfa_offset 16
 ; NOPIC-NEXT:    callq f@PLT # encoding: [0xe8,A,A,A,A]
-; NOPIC-NEXT:    # fixup A - offset: 1, value: f@PLT-4, kind: FK_PCRel_4
+; NOPIC-NEXT:    # fixup A - offset: 1, value: f@PLT, kind: FK_PCRel_4
 ; NOPIC-NEXT:    popq %rax # encoding: [0x58]
 ; NOPIC-NEXT:    .cfi_def_cfa_offset 8
 ; NOPIC-NEXT:  .LBB1_2: # %f
@@ -75,12 +75,12 @@ define void @foo32(i64 %val) {
 ; PIC-NEXT:    cmpq $cmp32, %rdi # encoding: [0x48,0x81,0xff,A,A,A,A]
 ; PIC-NEXT:    # fixup A - offset: 3, value: cmp32, kind: reloc_signed_4byte
 ; PIC-NEXT:    ja .LBB1_2 # encoding: [0x77,A]
-; PIC-NEXT:    # fixup A - offset: 1, value: .LBB1_2-1, kind: FK_PCRel_1
+; PIC-NEXT:    # fixup A - offset: 1, value: .LBB1_2, kind: FK_PCRel_1
 ; PIC-NEXT:  # %bb.1: # %t
 ; PIC-NEXT:    pushq %rax # encoding: [0x50]
 ; PIC-NEXT:    .cfi_def_cfa_offset 16
 ; PIC-NEXT:    callq f@PLT # encoding: [0xe8,A,A,A,A]
-; PIC-NEXT:    # fixup A - offset: 1, value: f@PLT-4, kind: FK_PCRel_4
+; PIC-NEXT:    # fixup A - offset: 1, value: f@PLT, kind: FK_PCRel_4
 ; PIC-NEXT:    popq %rax # encoding: [0x58]
 ; PIC-NEXT:    .cfi_def_cfa_offset 8
 ; PIC-NEXT:  .LBB1_2: # %f