[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.

Reviewers: qcolombet, javed.absar, MatzeB, jonpa

Subscribers: jyknight, nemanjai, llvm-commits, nhaehnle, mcrosier, mgorny

Differential Revision: https://reviews.llvm.org/D30751

llvm-svn: 311038

1 files changed, 10 insertions, 17 deletions

diff --git a/llvm/test/CodeGen/AMDGPU/private-access-no-objects.ll b/llvm/test/CodeGen/AMDGPU/private-access-no-objects.ll
index cf0c7944d4c..0b80fc33531 100644
--- a/llvm/test/CodeGen/AMDGPU/private-access-no-objects.ll
+++ b/llvm/test/CodeGen/AMDGPU/private-access-no-objects.ll
@@ -1,6 +1,6 @@
 ; RUN: llc -mtriple=amdgcn--amdhsa -mcpu=fiji -verify-machineinstrs < %s | FileCheck -enable-var-scope -check-prefix=GCN -check-prefix=VI -check-prefix=OPT %s
 ; RUN: llc -mtriple=amdgcn--amdhsa -mcpu=hawaii -verify-machineinstrs < %s | FileCheck -enable-var-scope -check-prefix=GCN -check-prefix=CI -check-prefix=OPT %s
-; RUN: llc -mtriple=amdgcn--amdhsa -mcpu=iceland -verify-machineinstrs < %s | FileCheck -enable-var-scope -check-prefix=GCN -check-prefix=VI -check-prefix=OPT %s
+; RUN: llc -mtriple=amdgcn--amdhsa -mcpu=iceland -verify-machineinstrs < %s | FileCheck -enable-var-scope -check-prefix=GCN -check-prefix=VI -check-prefix=OPTICELAND %s
 ; RUN: llc -O0 -mtriple=amdgcn--amdhsa -mcpu=fiji -verify-machineinstrs < %s | FileCheck -enable-var-scope -check-prefix=GCN -check-prefix=OPTNONE %s
 
 ; There are no stack objects, but still a private memory access. The
@@ -8,10 +8,12 @@
 ; shifted down to the end of the used registers.
 
 ; GCN-LABEL: {{^}}store_to_undef:
-; OPT-DAG: s_mov_b64 s{{\[}}[[RSRC_LO:[0-9]+]]:{{[0-9]+\]}}, s[0:1]
-; OPT-DAG: s_mov_b64 s{{\[[0-9]+}}:[[RSRC_HI:[0-9]+]]{{\]}}, s[2:3]
-; OPT-DAG: s_mov_b32 [[SOFFSET:s[0-9]+]], s5{{$}}
-; OPT: buffer_store_dword v{{[0-9]+}}, v{{[0-9]+}}, s{{\[}}[[RSRC_LO]]:[[RSRC_HI]]{{\]}}, [[SOFFSET]] offen{{$}}
+; OPT: buffer_store_dword v{{[0-9]+}}, v{{[0-9]+}}, s[0:3], s5 offen{{$}}
+; The -mcpu=iceland case doesn't copy-propagate the same as the other two opt cases because the temp registers %SGPR88_SGPR89_SGPR90_SGPR91 and %SGPR93 are marked as non-allocatable by this subtarget.
+; OPTICELAND-DAG: s_mov_b64 s{{\[}}[[RSRC_LO:[0-9]+]]:{{[0-9]+\]}}, s[0:1]
+; OPTICELAND-DAG: s_mov_b64 s{{\[[0-9]+}}:[[RSRC_HI:[0-9]+]]{{\]}}, s[2:3]
+; OPTICELAND-DAG: s_mov_b32 [[SOFFSET:s[0-9]+]], s5{{$}}
+; OPTICELAND: buffer_store_dword v{{[0-9]+}}, v{{[0-9]+}}, s{{\[}}[[RSRC_LO]]:[[RSRC_HI]]{{\]}}, [[SOFFSET]] offen{{$}}
 
 ; -O0 should assume spilling, so the input scratch resource descriptor
 ; -should be used directly without any copies.
@@ -24,30 +26,21 @@ define amdgpu_kernel void @store_to_undef() #0 {
 }
 
 ; GCN-LABEL: {{^}}store_to_inttoptr:
-; OPT-DAG: s_mov_b64 s{{\[}}[[RSRC_LO:[0-9]+]]:{{[0-9]+\]}}, s[0:1]
-; OPT-DAG: s_mov_b64 s{{\[[0-9]+}}:[[RSRC_HI:[0-9]+]]{{\]}}, s[2:3]
-; OPT-DAG: s_mov_b32 [[SOFFSET:s[0-9]+]], s5{{$}}
-; OPT: buffer_store_dword v{{[0-9]+}}, off, s{{\[}}[[RSRC_LO]]:[[RSRC_HI]]{{\]}}, [[SOFFSET]] offset:124{{$}}
+; OPT: buffer_store_dword v{{[0-9]+}}, off, s[0:3], s5 offset:124{{$}}
 define amdgpu_kernel void @store_to_inttoptr() #0 {
  store volatile i32 0, i32* inttoptr (i32 124 to i32*)
  ret void
 }
 
 ; GCN-LABEL: {{^}}load_from_undef:
-; OPT-DAG: s_mov_b64 s{{\[}}[[RSRC_LO:[0-9]+]]:{{[0-9]+\]}}, s[0:1]
-; OPT-DAG: s_mov_b64 s{{\[[0-9]+}}:[[RSRC_HI:[0-9]+]]{{\]}}, s[2:3]
-; OPT-DAG: s_mov_b32 [[SOFFSET:s[0-9]+]], s5{{$}}
-; OPT: buffer_load_dword v{{[0-9]+}}, v{{[0-9]+}}, s{{\[}}[[RSRC_LO]]:[[RSRC_HI]]{{\]}}, [[SOFFSET]] offen{{$}}
+; OPT: buffer_load_dword v{{[0-9]+}}, v{{[0-9]+}}, s[0:3], s5 offen{{$}}
 define amdgpu_kernel void @load_from_undef() #0 {
   %ld = load volatile i32, i32* undef
   ret void
 }
 
 ; GCN-LABEL: {{^}}load_from_inttoptr:
-; OPT-DAG: s_mov_b64 s{{\[}}[[RSRC_LO:[0-9]+]]:{{[0-9]+\]}}, s[0:1]
-; OPT-DAG: s_mov_b64 s{{\[[0-9]+}}:[[RSRC_HI:[0-9]+]]{{\]}}, s[2:3]
-; OPT-DAG: s_mov_b32 [[SOFFSET:s[0-9]+]], s5{{$}}
-; OPT: buffer_load_dword v{{[0-9]+}}, off, s{{\[}}[[RSRC_LO]]:[[RSRC_HI]]{{\]}}, [[SOFFSET]] offset:124{{$}}
+; OPT: buffer_load_dword v{{[0-9]+}}, off, s[0:3], s5 offset:124{{$}}
 define amdgpu_kernel void @load_from_inttoptr() #0 {
   %ld = load volatile i32, i32* inttoptr (i32 124 to i32*)
   ret void