[llvm] 7acc1f1 - [Test] Add tests showing instcombine sinking opportunity (NFC)

[Dmitry Makogon via llvm-commits]

Author: Dmitry Makogon
Date: 2022-09-16T15:06:00+07:00
New Revision: 7acc1f1fb1197bc4b7ccd84aeeb4cd93acb6f18a

URL: https://github.com/llvm/llvm-project/commit/7acc1f1fb1197bc4b7ccd84aeeb4cd93acb6f18a
DIFF: https://github.com/llvm/llvm-project/commit/7acc1f1fb1197bc4b7ccd84aeeb4cd93acb6f18a.diff

LOG: [Test] Add tests showing instcombine sinking opportunity (NFC)

InstCombine could sink instruction to NCD of its users.

Added: 
    llvm/test/Transforms/InstCombine/sink-into-ncd.ll

Modified: 
    

Removed: 
    


################################################################################
diff  --git a/llvm/test/Transforms/InstCombine/sink-into-ncd.ll b/llvm/test/Transforms/InstCombine/sink-into-ncd.ll
new file mode 100644
index 0000000000000..271edc0232cd3
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/sink-into-ncd.ll
@@ -0,0 +1,94 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=instcombine -S < %s | FileCheck %s
+
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc18.0.0"
+
+declare i32 @use(i8*)
+
+; Should be able to sink %ptr load to %not.null block which is the NCD of %ptr users.
+define i32 @test1(i8** %addr, i1 %c) {
+; CHECK-LABEL: @test1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[PTR:%.*]] = load i8*, i8** [[ADDR:%.*]], align 8
+; CHECK-NEXT:    br i1 false, label [[NULL:%.*]], label [[NOT_NULL:%.*]]
+; CHECK:       null:
+; CHECK-NEXT:    br label [[EXIT:%.*]]
+; CHECK:       not.null:
+; CHECK-NEXT:    [[Y:%.*]] = call i32 @use(i8* [[PTR]])
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[EXIT]], label [[NOT_NULL_2:%.*]]
+; CHECK:       not.null.2:
+; CHECK-NEXT:    [[Z:%.*]] = call i32 @use(i8* [[PTR]])
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[P:%.*]] = phi i32 [ poison, [[NULL]] ], [ [[Y]], [[NOT_NULL]] ], [ [[Z]], [[NOT_NULL_2]] ]
+; CHECK-NEXT:    ret i32 [[P]]
+;
+entry:
+  %ptr = load i8*, i8** %addr
+  %cond = icmp eq i8** %addr, null
+  br i1 %cond, label %null, label %not.null
+
+null:
+  %x = call i32 @use(i8* null)
+  br label %exit
+
+not.null:
+  %y = call i32 @use(i8* %ptr)
+  br i1 %c, label %exit, label %not.null.2
+
+not.null.2:
+  %z = call i32 @use(i8* %ptr)
+  br label %exit
+
+exit:
+  %p = phi i32 [ %x, %null ], [ %y, %not.null ], [ %z, %not.null.2 ]
+  ret i32 %p
+}
+
+; Should be able to sink %ptr load to %not.null block which is the NCD of %ptr users.
+define i32 @test2(i8** %addr, i1 %c) {
+; CHECK-LABEL: @test2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[COND:%.*]] = icmp eq i8** [[ADDR:%.*]], null
+; CHECK-NEXT:    br i1 [[COND]], label [[EXIT:%.*]], label [[LOAD_BB:%.*]]
+; CHECK:       load.bb:
+; CHECK-NEXT:    [[PTR:%.*]] = load i8*, i8** [[ADDR]], align 8
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[LEFT:%.*]], label [[RIGHT:%.*]]
+; CHECK:       left:
+; CHECK-NEXT:    [[X:%.*]] = call i32 @use(i8* null)
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       right:
+; CHECK-NEXT:    [[Y:%.*]] = call i32 @use(i8* [[PTR]])
+; CHECK-NEXT:    br i1 [[C]], label [[EXIT]], label [[RIGHT_2:%.*]]
+; CHECK:       right.2:
+; CHECK-NEXT:    [[Z:%.*]] = call i32 @use(i8* [[PTR]])
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[P:%.*]] = phi i32 [ [[X]], [[LEFT]] ], [ [[Y]], [[RIGHT]] ], [ [[Z]], [[RIGHT_2]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    ret i32 [[P]]
+;
+entry:
+  %cond = icmp eq i8** %addr, null
+  br i1 %cond, label %exit, label %load.bb
+
+load.bb:
+  %ptr = load i8*, i8** %addr
+  br i1 %c, label %left, label %right
+
+left:
+  %x = call i32 @use(i8* null)
+  br label %exit
+
+right:
+  %y = call i32 @use(i8* %ptr)
+  br i1 %c, label %exit, label %right.2
+
+right.2:
+  %z = call i32 @use(i8* %ptr)
+  br label %exit
+
+exit:
+  %p = phi i32 [ %x, %left ], [ %y, %right ], [ %z, %right.2 ], [ 0, %entry ]
+  ret i32 %p
+}