[llvm] 97b5736 - [SimplifyCFG] add a test for branch folding multiple BB
Yaxun Liu via llvm-commits
llvm-commits at lists.llvm.org
Sat Sep 17 18:19:54 PDT 2022
Author: Yaxun (Sam) Liu
Date: 2022-09-17T21:17:55-04:00
New Revision: 97b5736975f30d64cf6c447b0f0cb319134fa60b
URL: https://github.com/llvm/llvm-project/commit/97b5736975f30d64cf6c447b0f0cb319134fa60b
DIFF: https://github.com/llvm/llvm-project/commit/97b5736975f30d64cf6c447b0f0cb319134fa60b.diff
LOG: [SimplifyCFG] add a test for branch folding multiple BB
Reviewed by: Florian Hahn
Differential Revision: https://reviews.llvm.org/D132910
Added:
llvm/test/Transforms/SimplifyCFG/branch-fold-multiple.ll
Modified:
Removed:
################################################################################
diff --git a/llvm/test/Transforms/SimplifyCFG/branch-fold-multiple.ll b/llvm/test/Transforms/SimplifyCFG/branch-fold-multiple.ll
new file mode 100644
index 0000000000000..fd400632a5916
--- /dev/null
+++ b/llvm/test/Transforms/SimplifyCFG/branch-fold-multiple.ll
@@ -0,0 +1,151 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt %s -S -o - -passes=simplifycfg | FileCheck %s
+
+%struct.S = type { [4 x i32] }
+
+; Check the second, third, and fourth basic blocks are folded into
+; the first basic block since each has one bonus intruction, which
+; does not exceed the default bouns instruction threshold of 1.
+
+define i1 @test1(i32 %0, i32 %1, i32 %2, i32 %3) {
+; CHECK-LABEL: @test1(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[MUL0:%.*]] = mul i32 [[TMP0:%.*]], [[TMP0]]
+; CHECK-NEXT: [[CMP2:%.*]] = icmp sgt i32 [[MUL0]], 0
+; CHECK-NEXT: [[MUL1:%.*]] = mul i32 [[TMP1:%.*]], [[TMP1]]
+; CHECK-NEXT: [[CMP2_1:%.*]] = icmp sgt i32 [[MUL1]], 0
+; CHECK-NEXT: [[OR_COND:%.*]] = select i1 [[CMP2]], i1 true, i1 [[CMP2_1]]
+; CHECK-NEXT: [[MUL2:%.*]] = mul i32 [[TMP2:%.*]], [[TMP2]]
+; CHECK-NEXT: [[CMP2_2:%.*]] = icmp sgt i32 [[MUL2]], 0
+; CHECK-NEXT: [[OR_COND1:%.*]] = select i1 [[OR_COND]], i1 true, i1 [[CMP2_2]]
+; CHECK-NEXT: [[MUL3:%.*]] = mul i32 [[TMP3:%.*]], [[TMP3]]
+; CHECK-NEXT: [[CMP2_3:%.*]] = icmp sgt i32 [[MUL3]], 0
+; CHECK-NEXT: [[OR_COND2:%.*]] = select i1 [[OR_COND1]], i1 true, i1 [[CMP2_3]]
+; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[OR_COND2]], i1 false, i1 true
+; CHECK-NEXT: ret i1 [[SPEC_SELECT]]
+;
+entry:
+ %mul0 = mul i32 %0, %0
+ %cmp2 = icmp sgt i32 %mul0, 0
+ br i1 %cmp2, label %cleanup, label %for.cond
+
+for.cond:
+ %mul1 = mul i32 %1, %1
+ %cmp2.1 = icmp sgt i32 %mul1, 0
+ br i1 %cmp2.1, label %cleanup, label %for.cond.1
+
+for.cond.1:
+ %mul2 = mul i32 %2, %2
+ %cmp2.2 = icmp sgt i32 %mul2, 0
+ br i1 %cmp2.2, label %cleanup, label %for.cond.2
+
+for.cond.2:
+ %mul3 = mul i32 %3, %3
+ %cmp2.3 = icmp sgt i32 %mul3, 0
+ br i1 %cmp2.3, label %cleanup, label %for.cond.3
+
+for.cond.3:
+ br label %cleanup
+
+cleanup:
+ %cmp = phi i1 [ false, %entry ], [ false, %for.cond ], [ false, %for.cond.1 ], [ false, %for.cond.2 ], [ true, %for.cond.3 ]
+ ret i1 %cmp
+}
+
+; Check the second, third, and forth basic blocks are folded into the first
+; basic block since each has no bonus instruction.
+
+define i1 @test2(i32 %0, i32 %1, i32 %2, i32 %3) {
+; CHECK-LABEL: @test2(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[CMP2:%.*]] = icmp sgt i32 [[TMP0:%.*]], 0
+; CHECK-NEXT: [[CMP2_1:%.*]] = icmp sgt i32 [[TMP1:%.*]], 0
+; CHECK-NEXT: [[OR_COND:%.*]] = select i1 [[CMP2]], i1 true, i1 [[CMP2_1]]
+; CHECK-NEXT: [[CMP2_2:%.*]] = icmp sgt i32 [[TMP2:%.*]], 0
+; CHECK-NEXT: [[OR_COND1:%.*]] = select i1 [[OR_COND]], i1 true, i1 [[CMP2_2]]
+; CHECK-NEXT: [[CMP2_3:%.*]] = icmp sgt i32 [[TMP3:%.*]], 0
+; CHECK-NEXT: [[OR_COND2:%.*]] = select i1 [[OR_COND1]], i1 true, i1 [[CMP2_3]]
+; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[OR_COND2]], i1 false, i1 true
+; CHECK-NEXT: ret i1 [[SPEC_SELECT]]
+;
+entry:
+ %cmp2 = icmp sgt i32 %0, 0
+ br i1 %cmp2, label %cleanup, label %for.cond
+
+for.cond:
+ %cmp2.1 = icmp sgt i32 %1, 0
+ br i1 %cmp2.1, label %cleanup, label %for.cond.1
+
+for.cond.1:
+ %cmp2.2 = icmp sgt i32 %2, 0
+ br i1 %cmp2.2, label %cleanup, label %for.cond.2
+
+for.cond.2:
+ %cmp2.3 = icmp sgt i32 %3, 0
+ br i1 %cmp2.3, label %cleanup, label %for.cond.3
+
+for.cond.3:
+ br label %cleanup
+
+cleanup:
+ %cmp = phi i1 [ false, %entry ], [ false, %for.cond ], [ false, %for.cond.1 ], [ false, %for.cond.2 ], [ true, %for.cond.3 ]
+ ret i1 %cmp
+}
+
+; Check the second basic block is not folded into the first basic block
+; since it has three bonus instructions, which exceeds the default bonus
+; instruction threshold of 1. The third and fourth basic blocks are folded
+; into the second basic block since they do not have bonus instruction.
+
+define i1 @test3(i32 %0, i32 %1, i32 %2, i32 %3) {
+; CHECK-LABEL: @test3(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[CMP2:%.*]] = icmp sgt i32 [[TMP0:%.*]], 0
+; CHECK-NEXT: br i1 [[CMP2]], label [[CLEANUP:%.*]], label [[FOR_COND:%.*]]
+; CHECK: for.cond:
+; CHECK-NEXT: [[MUL1:%.*]] = mul i32 [[TMP0]], [[TMP1:%.*]]
+; CHECK-NEXT: [[MUL2:%.*]] = mul i32 [[MUL1]], [[TMP2:%.*]]
+; CHECK-NEXT: [[MUL3:%.*]] = mul i32 [[MUL2]], [[TMP3:%.*]]
+; CHECK-NEXT: [[MUL4:%.*]] = mul i32 [[MUL3]], [[TMP3]]
+; CHECK-NEXT: [[MUL5:%.*]] = mul i32 [[MUL4]], [[TMP3]]
+; CHECK-NEXT: [[MUL6:%.*]] = mul i32 [[MUL5]], [[TMP3]]
+; CHECK-NEXT: [[CMP2_1:%.*]] = icmp sgt i32 [[MUL5]], 0
+; CHECK-NEXT: [[CMP2_2:%.*]] = icmp sgt i32 [[TMP2]], 0
+; CHECK-NEXT: [[OR_COND:%.*]] = select i1 [[CMP2_1]], i1 true, i1 [[CMP2_2]]
+; CHECK-NEXT: [[CMP2_3:%.*]] = icmp sgt i32 [[TMP3]], 0
+; CHECK-NEXT: [[OR_COND1:%.*]] = select i1 [[OR_COND]], i1 true, i1 [[CMP2_3]]
+; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[OR_COND1]], i1 false, i1 true
+; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: cleanup:
+; CHECK-NEXT: [[CMP:%.*]] = phi i1 [ false, [[ENTRY:%.*]] ], [ [[SPEC_SELECT]], [[FOR_COND]] ]
+; CHECK-NEXT: ret i1 [[CMP]]
+;
+entry:
+ %cmp2 = icmp sgt i32 %0, 0
+ br i1 %cmp2, label %cleanup, label %for.cond
+
+for.cond:
+ %mul1 = mul i32 %0, %1
+ %mul2 = mul i32 %mul1, %2
+ %mul3 = mul i32 %mul2, %3
+ %mul4 = mul i32 %mul3, %3
+ %mul5 = mul i32 %mul4, %3
+ %mul6 = mul i32 %mul5, %3
+ %cmp2.1 = icmp sgt i32 %mul5, 0
+ br i1 %cmp2.1, label %cleanup, label %for.cond.1
+
+for.cond.1:
+ %cmp2.2 = icmp sgt i32 %2, 0
+ br i1 %cmp2.2, label %cleanup, label %for.cond.2
+
+for.cond.2:
+ %cmp2.3 = icmp sgt i32 %3, 0
+ br i1 %cmp2.3, label %cleanup, label %for.cond.3
+
+for.cond.3:
+ br label %cleanup
+
+cleanup:
+ %cmp = phi i1 [ false, %entry ], [ false, %for.cond ], [ false, %for.cond.1 ], [ false, %for.cond.2 ], [ true, %for.cond.3 ]
+ ret i1 %cmp
+}
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