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clang-p2996/llvm/test/CodeGen/MIR/X86/successor-basic-blocks.mir
Alex Lorenz 5022f6bb81 MIR Serialization: Change MIR syntax - use custom syntax for MBBs.
This commit modifies the way the machine basic blocks are serialized - now the
machine basic blocks are serialized using a custom syntax instead of relying on
YAML primitives. Instead of using YAML mappings to represent the individual
machine basic blocks in a machine function's body, the new syntax uses a single
YAML block scalar which contains all of the machine basic blocks and
instructions for that function.

This is an example of a function's body that uses the old syntax:

    body:
      - id: 0
        name: entry
        instructions:
          - '%eax = MOV32r0 implicit-def %eflags'
          - 'RETQ %eax'
    ...

The same body is now written like this:

    body: |
      bb.0.entry:
        %eax = MOV32r0 implicit-def %eflags
        RETQ %eax
    ...

This syntax change is motivated by the fact that the bundled machine
instructions didn't map that well to the old syntax which was using a single
YAML sequence to store all of the machine instructions in a block. The bundled
machine instructions internally use flags like BundledPred and BundledSucc to
determine the bundles, and serializing them as MI flags using the old syntax
would have had a negative impact on the readability and the ease of editing
for MIR files. The new syntax allows me to serialize the bundled machine
instructions using a block construct without relying on the internal flags,
for example:

   BUNDLE implicit-def dead %itstate, implicit-def %s1 ... {
      t2IT 1, 24, implicit-def %itstate
      %s1 = VMOVS killed %s0, 1, killed %cpsr, implicit killed %itstate
   }

This commit also converts the MIR testcases to the new syntax. I developed
a script that can convert from the old syntax to the new one. I will post the
script on the llvm-commits mailing list in the thread for this commit.

llvm-svn: 244982
2015-08-13 23:10:16 +00:00

84 lines
1.6 KiB
YAML

# RUN: llc -march=x86-64 -start-after branch-folder -stop-after branch-folder -o /dev/null %s | FileCheck %s
# This test ensures that the MIR parser parses basic block successors correctly.
--- |
define i32 @foo(i32 %a) {
entry:
%0 = icmp sle i32 %a, 10
br i1 %0, label %less, label %exit
less:
ret i32 0
exit:
ret i32 %a
}
define i32 @bar(i32 %a) {
entry:
%b = icmp sle i32 %a, 10
br i1 %b, label %0, label %1
; <label>:0
ret i32 0
; <label>:1
ret i32 %a
}
...
---
name: foo
body: |
; CHECK-LABEL: bb.0.entry:
; CHECK: successors: %bb.1.less, %bb.2.exit
; CHECK-LABEL: bb.1.less:
bb.0.entry:
successors: %bb.1.less, %bb.2.exit
liveins: %edi
CMP32ri8 %edi, 10, implicit-def %eflags
JG_1 %bb.2.exit, implicit killed %eflags
bb.1.less:
%eax = MOV32r0 implicit-def dead %eflags
RETQ killed %eax
bb.2.exit:
liveins: %edi
%eax = COPY killed %edi
RETQ killed %eax
...
---
name: bar
body: |
; CHECK-LABEL: name: bar
; Verify that we can have multiple lists of successors that will be merged
; into one.
; CHECK-LABEL: bb.0.entry:
; CHECK: successors: %bb.1, %bb.2
bb.0.entry:
liveins: %edi
successors: %bb.1
successors: %bb.2
CMP32ri8 %edi, 10, implicit-def %eflags
JG_1 %bb.2, implicit killed %eflags
; Verify that we can have an empty list of successors.
; CHECK-LABEL: bb.1:
; CHECK-NEXT: %eax = MOV32r0 implicit-def dead %eflags
bb.1:
successors:
%eax = MOV32r0 implicit-def dead %eflags
RETQ killed %eax
bb.2:
liveins: %edi
%eax = COPY killed %edi
RETQ killed %eax
...