[GVN] Basic optimization remark support

[recommitting after the fix in r288307]

Follow-on patches will add more interesting cases.

The goal of this patch-set is to get the GVN messages printed in
opt-viewer from Dhrystone as was presented in my Dev Meeting talk.  This
is the optimization view for the function (the last remark in the
function has a bug which is fixed in this series):
http://lab.llvm.org:8080/artifacts/opt-view_test-suite/build/SingleSource/Benchmarks/Dhrystone/CMakeFiles/dry.dir/html/_org_test-suite_SingleSource_Benchmarks_Dhrystone_dry.c.html#L430

Differential Revision: https://reviews.llvm.org/D26488

llvm-svn: 288370

1 files changed, 59 insertions, 0 deletions

diff --git a/llvm/test/Transforms/GVN/opt-remarks.ll b/llvm/test/Transforms/GVN/opt-remarks.ll
new file mode 100644
index 00000000000..c451833f765
--- /dev/null
+++ b/llvm/test/Transforms/GVN/opt-remarks.ll
@@ -0,0 +1,59 @@
+; RUN: opt < %s -gvn -o /dev/null  -pass-remarks-output=%t -S -pass-remarks=gvn \
+; RUN:     2>&1 | FileCheck %s
+; RUN: cat %t | FileCheck -check-prefix=YAML %s
+
+; CHECK:      remark: <unknown>:0:0: load of type i32 eliminated{{$}}
+; CHECK-NEXT: remark: <unknown>:0:0: load of type i32 eliminated{{$}}
+; CHECK-NEXT: remark: <unknown>:0:0: load of type i32 eliminated{{$}}
+; CHECK-NOT:  remark:
+
+; YAML:      --- !Passed
+; YAML-NEXT: Pass:            gvn
+; YAML-NEXT: Name:            LoadElim
+; YAML-NEXT: Function:        arg
+; YAML-NEXT: Args:
+; YAML-NEXT:   - String:          'load of type '
+; YAML-NEXT:   - Type:            i32
+; YAML-NEXT:   - String:          ' eliminated'
+; YAML-NEXT: ...
+; YAML-NEXT: --- !Passed
+; YAML-NEXT: Pass:            gvn
+; YAML-NEXT: Name:            LoadElim
+; YAML-NEXT: Function:        const
+; YAML-NEXT: Args:
+; YAML-NEXT:   - String:          'load of type '
+; YAML-NEXT:   - Type:            i32
+; YAML-NEXT:   - String:          ' eliminated'
+; YAML-NEXT: ...
+; YAML-NEXT: --- !Passed
+; YAML-NEXT: Pass:            gvn
+; YAML-NEXT: Name:            LoadElim
+; YAML-NEXT: Function:        inst
+; YAML-NEXT: Args:
+; YAML-NEXT:   - String:          'load of type '
+; YAML-NEXT:   - Type:            i32
+; YAML-NEXT:   - String:          ' eliminated'
+; YAML-NEXT: ...
+
+
+define i32 @arg(i32* %p, i32 %i) {
+entry:
+  store i32 %i, i32* %p
+  %load = load i32, i32* %p
+  ret i32 %load
+}
+
+define i32 @const(i32* %p) {
+entry:
+  store i32 4, i32* %p
+  %load = load i32, i32* %p
+  ret i32 %load
+}
+
+define i32 @inst(i32* %p) {
+entry:
+  %load1 = load i32, i32* %p
+  %load = load i32, i32* %p
+  %add = add i32 %load1, %load
+  ret i32 %add
+}