MachineCopyPropagation: Keep scanning through instructions with regmasks

This also simplifies the code by removing the overly conservative
NoInterveningSideEffect() function. This function checked:
- That the two copies belong to the same block: We only process one
  block at a time and clear our maps in between it is impossible to find a
  copy from a different block.
- There is no terminator between the two copy instructions: This is not
  allowed anyway (the MachineVerifier would complain)
- Does not have instructions with hasUnmodeledSideEffects() or isCall()
  set: Even for those instructuction we must have all clobbers/defs of
  registers explicit as an operand. If the register is explicitely
  clobbered we would never come to the point of checking for
  NoInterveningSideEffect() anyway.

(I also checked this with a temporary build of the test-suite with all
 potentially failing conditions in NoInterveningSideEffect() turned into
 asserts)

Differential Revision: http://reviews.llvm.org/D17474

llvm-svn: 261965

1 files changed, 59 insertions, 4 deletions

diff --git a/llvm/test/CodeGen/X86/machine-copy-prop.mir b/llvm/test/CodeGen/X86/machine-copy-prop.mir
index 85d38225a46..cf566edf253 100644
--- a/llvm/test/CodeGen/X86/machine-copy-prop.mir
+++ b/llvm/test/CodeGen/X86/machine-copy-prop.mir
@@ -1,13 +1,16 @@
-# RUN: llc -march=x86 -run-pass machine-cp -verify-machineinstrs -o /dev/null %s 2>&1 | FileCheck %s
+# RUN: llc -march=x86 -run-pass machine-cp -o /dev/null %s 2>&1 | FileCheck %s
 
 --- |
   declare void @foo()
   define void @copyprop_remove_kill0() { ret void }
   define void @copyprop_remove_kill1() { ret void }
   define void @copyprop_remove_kill2() { ret void }
+  define void @copyprop0() { ret void }
+  define void @nocopyprop0() { ret void }
+  define void @nocopyprop1() { ret void }
 ...
 ---
-# The second copy is redundand and will be removed, check that we also remove
+# The second copy is redundant and will be removed, check that we also remove
 # the kill flag of intermediate instructions.
 # CHECK-LABEL: name: copyprop_remove_kill0
 # CHECK: bb.0:
@@ -24,7 +27,7 @@ body: |
     NOOP implicit %rax, implicit %rdi
 ...
 ---
-# The second copy is redundand and will be removed, check that we also remove
+# The second copy is redundant and will be removed, check that we also remove
 # the kill flag of intermediate instructions.
 # CHECK-LABEL: name: copyprop_remove_kill1
 # CHECK: bb.0:
@@ -41,7 +44,7 @@ body: |
     NOOP implicit %rax, implicit %rdi
 ...
 ---
-# The second copy is redundand and will be removed, check that we also remove
+# The second copy is redundant and will be removed, check that we also remove
 # the kill flag of intermediate instructions.
 # CHECK-LABEL: name: copyprop_remove_kill2
 # CHECK: bb.0:
@@ -57,3 +60,55 @@ body: |
     %di = COPY %ax
     NOOP implicit %rax, implicit %rdi
 ...
+---
+# The second copy is redundant; the call preserves the source and dest register.
+# CHECK-LABEL: name: copyprop0
+# CHECK: bb.0:
+# CHECK-NEXT: %rax = COPY %rdi
+# CHECK-NEXT: CALL64pcrel32 @foo, csr_64_rt_mostregs
+# CHECK-NEXT: NOOP implicit %edi
+# CHECK-NOT: COPY
+# CHECK-NEXT: NOOP implicit %rax, implicit %rdi
+name: copyprop0
+body: |
+  bb.0:
+    %rax = COPY %rdi
+    CALL64pcrel32 @foo, csr_64_rt_mostregs
+    NOOP implicit killed %edi
+    %rdi = COPY %rax
+    NOOP implicit %rax, implicit %rdi
+...
+---
+# The second copy is not redundant if the source register (%rax) is clobbered
+# even if the dest (%rbp) is not.
+# CHECK-LABEL: name: nocopyprop0
+# CHECK: bb.0:
+# CHECK-NEXT: %rax = COPY %rbp
+# CHECK-NEXT: CALL64pcrel32 @foo, csr_64, implicit %rax, implicit %rbp
+# CHECK-NEXT: %rbp = COPY %rax
+# CHECK-NEXT: NOOP implicit %rax, implicit %rbp
+name: nocopyprop0
+body: |
+  bb.0:
+    %rax = COPY %rbp
+    CALL64pcrel32 @foo, csr_64, implicit %rax, implicit %rbp
+    %rbp = COPY %rax
+    NOOP implicit %rax, implicit %rbp
+...
+---
+# The second copy is not redundant if the dest register (%rax) is clobbered
+# even if the source (%rbp) is not.
+# CHECK-LABEL: name: nocopyprop1
+# CHECK: bb.0:
+# CHECK-NEXT: %rbp = COPY %rax
+# CHECK-NEXT: CALL64pcrel32 @foo, csr_64, implicit %rax, implicit %rbp
+# CHECK-NEXT: %rax = COPY %rbp
+# CHECK-NEXT: NOOP implicit %rax, implicit %rbp
+name: nocopyprop1
+body: |
+  bb.0:
+    %rbp = COPY %rax
+    CALL64pcrel32 @foo, csr_64, implicit %rax, implicit %rbp
+    %rax = COPY %rbp
+    NOOP implicit %rax, implicit %rbp
+...