Revert r312154 "Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding""

It caused PR34387: Assertion failed: (RegNo < NumRegs && "Attempting to access record for invalid register number!")

> Issues identified by buildbots addressed since original review:
> - Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907.
> - The pass no longer forwards COPYs to physical register uses, since
>   doing so can break code that implicitly relies on the physical
>   register number of the use.
> - The pass no longer forwards COPYs to undef uses, since doing so
>   can break the machine verifier by creating LiveRanges that don't
>   end on a use (since the undef operand is not considered a use).
>
>   [MachineCopyPropagation] Extend pass to do COPY source forwarding
>
>   This change extends MachineCopyPropagation to do COPY source forwarding.
>
>   This change also extends the MachineCopyPropagation pass to be able to
>   be run during register allocation, after physical registers have been
>   assigned, but before the virtual registers have been re-written, which
>   allows it to remove virtual register COPY LiveIntervals that become dead
>   through the forwarding of all of their uses.

llvm-svn: 312178

1 files changed, 0 insertions, 9 deletions

diff --git a/llvm/lib/CodeGen/TargetPassConfig.cpp b/llvm/lib/CodeGen/TargetPassConfig.cpp
index c76903a24da..34d96a81130 100644
--- a/llvm/lib/CodeGen/TargetPassConfig.cpp
+++ b/llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -88,8 +88,6 @@ static cl::opt<bool> DisableCGP("disable-cgp", cl::Hidden,
     cl::desc("Disable Codegen Prepare"));
 static cl::opt<bool> DisableCopyProp("disable-copyprop", cl::Hidden,
     cl::desc("Disable Copy Propagation pass"));
-static cl::opt<bool> DisableCopyPropPreRegRewrite("disable-copyprop-prerewrite", cl::Hidden,
-    cl::desc("Disable Copy Propagation Pre-Register Re-write pass"));
 static cl::opt<bool> DisablePartialLibcallInlining("disable-partial-libcall-inlining",
     cl::Hidden, cl::desc("Disable Partial Libcall Inlining"));
 static cl::opt<bool> EnableImplicitNullChecks(
@@ -250,9 +248,6 @@ static IdentifyingPassPtr overridePass(AnalysisID StandardID,
   if (StandardID == &MachineCopyPropagationID)
     return applyDisable(TargetID, DisableCopyProp);
 
-  if (StandardID == &MachineCopyPropagationPreRegRewriteID)
-    return applyDisable(TargetID, DisableCopyPropPreRegRewrite);
-
   return TargetID;
 }
 
@@ -1061,10 +1056,6 @@ void TargetPassConfig::addOptimizedRegAlloc(FunctionPass *RegAllocPass) {
     // Allow targets to change the register assignments before rewriting.
     addPreRewrite();
 
-    // Copy propagate to forward register uses and try to eliminate COPYs that
-    // were not coalesced.
-    addPass(&MachineCopyPropagationPreRegRewriteID);
-
     // Finally rewrite virtual registers.
     addPass(&VirtRegRewriterID);