[AMDGPU] Fix s_branch with -1 offset

Summary:
In case s_branch instruction target is itself backend should emit offset -1 but instead it emit 0.
'''
label:
    s_branch label  // should emit [0xff,0xff,0x82,0xbf]
'''

Tom, Matt: why are we adjusting fixup values in applyFixup() method instead of processFixup()? processFixup() is calling adjustFixupValue() but does nothing with its result.

Reviewers: vpykhtin, artem.tamazov, tstellarAMD

Subscribers: arsenm, kzhuravl, wdng, nhaehnle, yaxunl

Differential Revision: https://reviews.llvm.org/D24671

llvm-svn: 281896

1 files changed, 2 insertions, 5 deletions

diff --git a/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp b/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp
index 2e02cbafd71..5b02b2848bf 100644
--- a/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp
+++ b/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp
@@ -133,24 +133,21 @@ void AMDGPUAsmBackend::processFixupValue(const MCAssembler &Asm,
                                          const MCValue &Target, uint64_t &Value,
                                          bool &IsResolved) {
   if (IsResolved)
-    (void)adjustFixupValue(Fixup, Value, &Asm.getContext());
-
+    Value = adjustFixupValue(Fixup, Value, &Asm.getContext());
 }
 
 void AMDGPUAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
                                   unsigned DataSize, uint64_t Value,
                                   bool IsPCRel) const {
-  unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());
   if (!Value)
     return; // Doesn't change encoding.
 
-  Value = adjustFixupValue(Fixup, Value, nullptr);
-
   MCFixupKindInfo Info = getFixupKindInfo(Fixup.getKind());
 
   // Shift the value into position.
   Value <<= Info.TargetOffset;
 
+  unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());
   uint32_t Offset = Fixup.getOffset();
   assert(Offset + NumBytes <= DataSize && "Invalid fixup offset!");