[llvm] b6676f3 - [LICM] Add test for single thread model promotion (NFC)

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2022-10-07T17:13:09+02:00
New Revision: b6676f3c12588cd1333de9bb3cee3a53bc71771e

URL: https://github.com/llvm/llvm-project/commit/b6676f3c12588cd1333de9bb3cee3a53bc71771e
DIFF: https://github.com/llvm/llvm-project/commit/b6676f3c12588cd1333de9bb3cee3a53bc71771e.diff

LOG: [LICM] Add test for single thread model promotion (NFC)

Tests for D130466.

Added: 
    llvm/test/Transforms/LICM/promote-single-thread.ll

Modified: 
    

Removed: 
    


################################################################################
diff  --git a/llvm/test/Transforms/LICM/promote-single-thread.ll b/llvm/test/Transforms/LICM/promote-single-thread.ll
new file mode 100644
index 0000000000000..b0127344a523a
--- /dev/null
+++ b/llvm/test/Transforms/LICM/promote-single-thread.ll
@@ -0,0 +1,167 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -licm < %s | FileCheck %s
+
+ at g = external global i32
+ at c = external constant i32
+
+declare void @capture(ptr)
+
+; In single-thread mode both loads and stores can be promoted. In multi-thread
+; mode only loads can be promoted, as a 
diff erent thread might write to the
+; global.
+define void @promote_global(i1 %c, i1 %c2) {
+; CHECK-LABEL: @promote_global(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[G_PROMOTED:%.*]] = load i32, ptr @g, align 4
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[V_INC2:%.*]] = phi i32 [ [[V_INC1:%.*]], [[LATCH:%.*]] ], [ [[G_PROMOTED]], [[ENTRY:%.*]] ]
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[IF:%.*]], label [[LATCH]]
+; CHECK:       if:
+; CHECK-NEXT:    [[V_INC:%.*]] = add i32 [[V_INC2]], 1
+; CHECK-NEXT:    store i32 [[V_INC]], ptr @g, align 4
+; CHECK-NEXT:    br label [[LATCH]]
+; CHECK:       latch:
+; CHECK-NEXT:    [[V_INC1]] = phi i32 [ [[V_INC]], [[IF]] ], [ [[V_INC2]], [[LOOP]] ]
+; CHECK-NEXT:    br i1 [[C2:%.*]], label [[EXIT:%.*]], label [[LOOP]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %loop
+
+loop:
+  br i1 %c, label %if, label %latch
+
+if:
+  %v = load i32, ptr @g
+  %v.inc = add i32 %v, 1
+  store i32 %v.inc, ptr @g
+  br label %latch
+
+latch:
+  br i1 %c2, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+; The store can never be promoted here, because the global is constant, and
+; the store could trap.
+define void @promote_constant_global(i1 %c, i1 %c2) {
+; CHECK-LABEL: @promote_constant_global(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[V:%.*]] = load i32, ptr @c, align 4
+; CHECK-NEXT:    [[V_INC:%.*]] = add i32 [[V]], 1
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[IF:%.*]], label [[LATCH:%.*]]
+; CHECK:       if:
+; CHECK-NEXT:    store i32 [[V_INC]], ptr @c, align 4
+; CHECK-NEXT:    br label [[LATCH]]
+; CHECK:       latch:
+; CHECK-NEXT:    br i1 [[C2:%.*]], label [[EXIT:%.*]], label [[LOOP]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %loop
+
+loop:
+  br i1 %c, label %if, label %latch
+
+if:
+  %v = load i32, ptr @c
+  %v.inc = add i32 %v, 1
+  store i32 %v.inc, ptr @c
+  br label %latch
+
+latch:
+  br i1 %c2, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+; In single-thread mode both loads and stores can be promoted. In multi-thread
+; mode only loads can be promoted, as a 
diff erent thread might write to the
+; captured alloca.
+define void @promote_captured_alloca(i1 %c, i1 %c2) {
+; CHECK-LABEL: @promote_captured_alloca(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @capture(ptr [[A]])
+; CHECK-NEXT:    [[A_PROMOTED:%.*]] = load i32, ptr [[A]], align 4
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[V_INC2:%.*]] = phi i32 [ [[V_INC1:%.*]], [[LATCH:%.*]] ], [ [[A_PROMOTED]], [[ENTRY:%.*]] ]
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[IF:%.*]], label [[LATCH]]
+; CHECK:       if:
+; CHECK-NEXT:    [[V_INC:%.*]] = add i32 [[V_INC2]], 1
+; CHECK-NEXT:    store i32 [[V_INC]], ptr [[A]], align 4
+; CHECK-NEXT:    br label [[LATCH]]
+; CHECK:       latch:
+; CHECK-NEXT:    [[V_INC1]] = phi i32 [ [[V_INC]], [[IF]] ], [ [[V_INC2]], [[LOOP]] ]
+; CHECK-NEXT:    br i1 [[C2:%.*]], label [[EXIT:%.*]], label [[LOOP]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = alloca i32
+  call void @capture(ptr %a)
+  br label %loop
+
+loop:
+  br i1 %c, label %if, label %latch
+
+if:
+  %v = load i32, ptr %a
+  %v.inc = add i32 %v, 1
+  store i32 %v.inc, ptr %a
+  br label %latch
+
+latch:
+  br i1 %c2, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+; The store cannot be promoted here, because we do not know whether the
+; argument memory is writable.
+define void @promote_arg(ptr noalias dereferenceable(4) align 4 %arg, i1 %c, i1 %c2) {
+; CHECK-LABEL: @promote_arg(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ARG_PROMOTED:%.*]] = load i32, ptr [[ARG:%.*]], align 4
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[V_INC2:%.*]] = phi i32 [ [[V_INC1:%.*]], [[LATCH:%.*]] ], [ [[ARG_PROMOTED]], [[ENTRY:%.*]] ]
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[IF:%.*]], label [[LATCH]]
+; CHECK:       if:
+; CHECK-NEXT:    [[V_INC:%.*]] = add i32 [[V_INC2]], 1
+; CHECK-NEXT:    store i32 [[V_INC]], ptr [[ARG]], align 4
+; CHECK-NEXT:    br label [[LATCH]]
+; CHECK:       latch:
+; CHECK-NEXT:    [[V_INC1]] = phi i32 [ [[V_INC]], [[IF]] ], [ [[V_INC2]], [[LOOP]] ]
+; CHECK-NEXT:    br i1 [[C2:%.*]], label [[EXIT:%.*]], label [[LOOP]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %loop
+
+loop:
+  br i1 %c, label %if, label %latch
+
+if:
+  %v = load i32, ptr %arg
+  %v.inc = add i32 %v, 1
+  store i32 %v.inc, ptr %arg
+  br label %latch
+
+latch:
+  br i1 %c2, label %exit, label %loop
+
+exit:
+  ret void
+}