Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding"
Issues addressed since original review:
- Avoid bug in regalloc greedy/machine verifier when forwarding to use
in an instruction that re-defines the same virtual register.
- Fixed bug when forwarding to use in EarlyClobber instruction slot.
- Fixed incorrect forwarding to register definitions that showed up in
explicit_uses() iterator (e.g. in INLINEASM).
- Moved removal of dead instructions found by
LiveIntervals::shrinkToUses() outside of loop iterating over
instructions to avoid instructions being deleted while pointed to by
iterator.
- 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: 314729
diff --git a/llvm/test/CodeGen/AMDGPU/ret.ll b/llvm/test/CodeGen/AMDGPU/ret.ll
index 831c71d..2d673a9 100644
--- a/llvm/test/CodeGen/AMDGPU/ret.ll
+++ b/llvm/test/CodeGen/AMDGPU/ret.ll
@@ -2,10 +2,10 @@
; RUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs < %s | FileCheck -check-prefix=GCN %s
; GCN-LABEL: {{^}}vgpr:
-; GCN: v_mov_b32_e32 v1, v0
-; GCN-DAG: v_add_f32_e32 v0, 1.0, v1
-; GCN-DAG: exp mrt0 v1, v1, v1, v1 done vm
+; GCN-DAG: v_mov_b32_e32 v1, v0
+; GCN-DAG: exp mrt0 v0, v0, v0, v0 done vm
; GCN: s_waitcnt expcnt(0)
+; GCN: v_add_f32_e32 v0, 1.0, v0
; GCN-NOT: s_endpgm
define amdgpu_vs { float, float } @vgpr([9 x <16 x i8>] addrspace(2)* byval %arg, i32 inreg %arg1, i32 inreg %arg2, float %arg3) #0 {
bb:
@@ -204,13 +204,13 @@
}
; GCN-LABEL: {{^}}both:
-; GCN: v_mov_b32_e32 v1, v0
-; GCN-DAG: exp mrt0 v1, v1, v1, v1 done vm
-; GCN-DAG: v_add_f32_e32 v0, 1.0, v1
-; GCN-DAG: s_add_i32 s0, s3, 2
+; GCN-DAG: exp mrt0 v0, v0, v0, v0 done vm
+; GCN-DAG: v_mov_b32_e32 v1, v0
; GCN-DAG: s_mov_b32 s1, s2
-; GCN: s_mov_b32 s2, s3
; GCN: s_waitcnt expcnt(0)
+; GCN: v_add_f32_e32 v0, 1.0, v0
+; GCN-DAG: s_add_i32 s0, s3, 2
+; GCN-DAG: s_mov_b32 s2, s3
; GCN-NOT: s_endpgm
define amdgpu_vs { float, i32, float, i32, i32 } @both([9 x <16 x i8>] addrspace(2)* byval %arg, i32 inreg %arg1, i32 inreg %arg2, float %arg3) #0 {
bb: