[llvm] 13042da - [ConstraintElimination] Add support for And.
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Tue Nov 17 06:12:32 PST 2020
Author: Florian Hahn
Date: 2020-11-17T14:12:15Z
New Revision: 13042da5cb3fe5f17c58c2446c93635a2c432049
URL: https://github.com/llvm/llvm-project/commit/13042da5cb3fe5f17c58c2446c93635a2c432049
DIFF: https://github.com/llvm/llvm-project/commit/13042da5cb3fe5f17c58c2446c93635a2c432049.diff
LOG: [ConstraintElimination] Add support for And.
When processing conditional branches, if the condition is an AND of 2 compares
and the true successor only has the current block as predecessor, queue both
conditions for the true successor.
Added:
Modified:
llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
llvm/test/Transforms/ConstraintElimination/and.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index c43cb39a5918..01fead12dc08 100644
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -182,6 +182,21 @@ static bool eliminateConstraints(Function &F, DominatorTree &DT) {
continue;
}
+ // If the condition is an AND of 2 compares and the true successor only has
+ // the current block as predecessor, queue both conditions for the true
+ // successor.
+ if (match(Br->getCondition(), m_And(m_Cmp(), m_Cmp()))) {
+ BasicBlock *TrueSuccessor = Br->getSuccessor(0);
+ if (TrueSuccessor->getSinglePredecessor()) {
+ auto *AndI = cast<Instruction>(Br->getCondition());
+ WorkList.emplace_back(DT.getNode(TrueSuccessor),
+ cast<CmpInst>(AndI->getOperand(0)), false);
+ WorkList.emplace_back(DT.getNode(TrueSuccessor),
+ cast<CmpInst>(AndI->getOperand(1)), false);
+ }
+ continue;
+ }
+
auto *CmpI = dyn_cast<CmpInst>(Br->getCondition());
if (!CmpI)
continue;
diff --git a/llvm/test/Transforms/ConstraintElimination/and.ll b/llvm/test/Transforms/ConstraintElimination/and.ll
index 2e7f61659dac..d8962b39ebd5 100644
--- a/llvm/test/Transforms/ConstraintElimination/and.ll
+++ b/llvm/test/Transforms/ConstraintElimination/and.ll
@@ -12,11 +12,11 @@ define i32 @test_and_ule(i32 %x, i32 %y, i32 %z, i32 %a) {
; CHECK-NEXT: br i1 [[AND]], label [[BB1:%.*]], label [[EXIT:%.*]]
; CHECK: bb1:
; CHECK-NEXT: [[T_1:%.*]] = icmp ule i32 [[X]], [[Z]]
-; CHECK-NEXT: call void @use(i1 [[T_1]])
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[T_2:%.*]] = icmp ule i32 [[X]], [[Y]]
-; CHECK-NEXT: call void @use(i1 [[T_2]])
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[T_3:%.*]] = icmp ule i32 [[Y]], [[Z]]
-; CHECK-NEXT: call void @use(i1 [[T_3]])
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[C_3:%.*]] = icmp ule i32 [[X]], [[A:%.*]]
; CHECK-NEXT: call void @use(i1 [[C_3]])
; CHECK-NEXT: ret i32 10
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