[llvm] 0f37ba7 - [ValueTracking] Baseline tests for Power-of-2 value tracking on PHI nodes
William Huang via llvm-commits
llvm-commits at lists.llvm.org
Thu May 19 11:30:22 PDT 2022
Author: William Huang
Date: 2022-05-19T18:30:14Z
New Revision: 0f37ba7b236252b29c33335fb00836d81671ea65
URL: https://github.com/llvm/llvm-project/commit/0f37ba7b236252b29c33335fb00836d81671ea65
DIFF: https://github.com/llvm/llvm-project/commit/0f37ba7b236252b29c33335fb00836d81671ea65.diff
LOG: [ValueTracking] Baseline tests for Power-of-2 value tracking on PHI nodes
Reviewed By: davidxl
Differential Revision: https://reviews.llvm.org/D124885
Added:
llvm/test/Analysis/ValueTracking/known-power-of-two-urem.ll
Modified:
Removed:
################################################################################
diff --git a/llvm/test/Analysis/ValueTracking/known-power-of-two-urem.ll b/llvm/test/Analysis/ValueTracking/known-power-of-two-urem.ll
new file mode 100644
index 000000000000..880e14dae877
--- /dev/null
+++ b/llvm/test/Analysis/ValueTracking/known-power-of-two-urem.ll
@@ -0,0 +1,388 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -instcombine < %s | FileCheck %s
+
+; Check if a value can be deduced as a power of 2, allowing urem optimization.
+; i.e. A urem B = A & (B - 1) if B is a power of 2.
+
+define i64 @known_power_of_two_urem_phi(i64 %size, i1 %cmp, i1 %cmp1) {
+; CHECK-LABEL: @known_power_of_two_urem_phi(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br i1 [[CMP:%.*]], label [[COND_TRUE:%.*]], label [[COND_END:%.*]]
+; CHECK: cond.true:
+; CHECK-NEXT: br i1 [[CMP1:%.*]], label [[COND_TRUE_TRUE:%.*]], label [[COND_TRUE_FALSE:%.*]]
+; CHECK: cond.true.true:
+; CHECK-NEXT: br label [[COND_TRUE_END:%.*]]
+; CHECK: cond.true.false:
+; CHECK-NEXT: br label [[COND_TRUE_END]]
+; CHECK: cond.true.end:
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ 2, [[COND_TRUE_TRUE]] ], [ 4, [[COND_TRUE_FALSE]] ]
+; CHECK-NEXT: br label [[COND_END]]
+; CHECK: cond.end:
+; CHECK-NEXT: [[PHI1:%.*]] = phi i64 [ 4096, [[ENTRY:%.*]] ], [ [[PHI]], [[COND_TRUE_END]] ]
+; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI1]]
+; CHECK-NEXT: ret i64 [[UREM]]
+;
+entry:
+ br i1 %cmp, label %cond.true, label %cond.end
+
+cond.true:
+ br i1 %cmp1, label %cond.true.true, label %cond.true.false
+
+cond.true.true:
+ br label %cond.true.end
+
+cond.true.false:
+ br label %cond.true.end
+
+cond.true.end:
+ %phi = phi i64 [ 2, %cond.true.true ], [ 4, %cond.true.false ]
+ br label %cond.end
+
+cond.end:
+ %phi1 = phi i64 [ 4096, %entry ], [ %phi, %cond.true.end ]
+ %urem = urem i64 %size, %phi1
+ ret i64 %urem
+}
+
+define i64 @known_power_of_two_urem_nested_expr(i64 %size, i1 %cmp, i1 %cmp1, i64 %0) {
+; CHECK-LABEL: @known_power_of_two_urem_nested_expr(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br i1 [[CMP:%.*]], label [[COND_TRUE:%.*]], label [[COND_FALSE:%.*]]
+; CHECK: cond.true:
+; CHECK-NEXT: [[TMP1:%.*]] = shl nuw i64 1, [[TMP0:%.*]]
+; CHECK-NEXT: br label [[COND_END:%.*]]
+; CHECK: cond.false:
+; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[CMP1:%.*]], i64 2, i64 8
+; CHECK-NEXT: br label [[COND_END]]
+; CHECK: cond.end:
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ [[SELECT]], [[COND_FALSE]] ], [ [[TMP1]], [[COND_TRUE]] ], [ [[PHI]], [[COND_END]] ]
+; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]]
+; CHECK-NEXT: [[CMP2:%.*]] = icmp ult i64 [[UREM]], 10
+; CHECK-NEXT: br i1 [[CMP2]], label [[COND_END]], label [[END:%.*]]
+; CHECK: end:
+; CHECK-NEXT: ret i64 [[UREM]]
+;
+entry:
+ br i1 %cmp, label %cond.true, label %cond.false
+
+cond.true:
+ %1 = shl nuw i64 1, %0
+ br label %cond.end
+
+cond.false:
+ %select = select i1 %cmp1, i64 2, i64 8
+ br label %cond.end
+
+cond.end:
+ %phi = phi i64 [ %select, %cond.false ], [ %1, %cond.true ], [ %phi, %cond.end ]
+ %2 = phi i64 [ %size, %cond.false ], [ %size, %cond.true ], [ %0, %cond.end ]
+ %urem = urem i64 %size, %phi
+ %cmp2 = icmp ult i64 %urem, 10
+ br i1 %cmp2, label %cond.end, label %end
+
+end:
+ ret i64 %urem
+}
+
+define i64 @known_power_of_two_urem_negative(i64 %size, i1 %cmp, i64 %0) {
+; urem is not replaced if not all operands are power of 2.
+;
+; CHECK-LABEL: @known_power_of_two_urem_negative(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br i1 [[CMP:%.*]], label [[COND_TRUE:%.*]], label [[COND_END:%.*]]
+; CHECK: cond.true:
+; CHECK-NEXT: br label [[COND_END]]
+; CHECK: cond.end:
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ 4, [[ENTRY:%.*]] ], [ [[TMP0:%.*]], [[COND_TRUE]] ]
+; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]]
+; CHECK-NEXT: ret i64 [[UREM]]
+;
+entry:
+ br i1 %cmp, label %cond.true, label %cond.end
+
+cond.true:
+ br label %cond.end
+
+cond.end:
+ %phi = phi i64 [ 4, %entry ], [ %0, %cond.true ]
+ %urem = urem i64 %size, %phi
+ ret i64 %urem
+}
+
+define i64 @known_power_of_two_urem_loop_mul(i64 %size, i64 %a) {
+; CHECK-LABEL: @known_power_of_two_urem_loop_mul(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[START:%.*]] = shl nuw i64 1, [[A:%.*]]
+; CHECK-NEXT: br label [[FOR_BODY:%.*]]
+; CHECK: for.body:
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ [[START]], [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]]
+; CHECK-NEXT: [[ADD]] = add nuw i64 [[SUM]], [[UREM]]
+; CHECK-NEXT: [[I]] = shl nuw i64 [[PHI]], 2
+; CHECK-NEXT: [[ICMP:%.*]] = icmp ult i64 [[PHI]], 25000000
+; CHECK-NEXT: br i1 [[ICMP]], label [[FOR_BODY]], label [[FOR_END:%.*]]
+; CHECK: for.end:
+; CHECK-NEXT: ret i64 [[SUM]]
+;
+entry:
+ %start = shl nuw i64 1, %a
+ br label %for.body
+
+for.body:
+ %phi = phi i64 [ %start, %entry ], [ %i, %for.body ]
+ %sum = phi i64 [ 0, %entry ], [ %add, %for.body ]
+ %urem = urem i64 %size, %phi
+ %add = add nuw i64 %sum, %urem
+ %i = mul nuw i64 %phi, 4
+ %icmp = icmp ult i64 %i, 100000000
+ br i1 %icmp, label %for.body, label %for.end
+
+for.end:
+ %r = phi i64 [ %sum, %for.body ]
+ ret i64 %r
+}
+
+define i64 @known_power_of_two_urem_loop_mul_negative(i64 %size, i64 %a) {
+; Cannot deduce induction variable is a power of 2 if it is multiplied by 3.
+;
+; CHECK-LABEL: @known_power_of_two_urem_loop_mul_negative(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[START:%.*]] = shl nuw i64 1, [[A:%.*]]
+; CHECK-NEXT: br label [[FOR_BODY:%.*]]
+; CHECK: for.body:
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ [[START]], [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]]
+; CHECK-NEXT: [[ADD]] = add nuw i64 [[SUM]], [[UREM]]
+; CHECK-NEXT: [[I]] = mul nuw i64 [[PHI]], 3
+; CHECK-NEXT: [[ICMP:%.*]] = icmp ult i64 [[I]], 100000000
+; CHECK-NEXT: br i1 [[ICMP]], label [[FOR_BODY]], label [[FOR_END:%.*]]
+; CHECK: for.end:
+; CHECK-NEXT: ret i64 [[SUM]]
+;
+entry:
+ %start = shl nuw i64 1, %a
+ br label %for.body
+
+for.body:
+ %phi = phi i64 [ %start, %entry ], [ %i, %for.body ]
+ %sum = phi i64 [ 0, %entry ], [ %add, %for.body ]
+ %urem = urem i64 %size, %phi
+ %add = add nuw i64 %sum, %urem
+ %i = mul nuw i64 %phi, 3
+ %icmp = icmp ult i64 %i, 100000000
+ br i1 %icmp, label %for.body, label %for.end
+
+for.end:
+ %r = phi i64 [ %sum, %for.body ]
+ ret i64 %r
+}
+
+define i64 @known_power_of_two_urem_loop_shl(i64 %size, i64 %a) {
+; CHECK-LABEL: @known_power_of_two_urem_loop_shl(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[START:%.*]] = shl nuw i64 1, [[A:%.*]]
+; CHECK-NEXT: br label [[FOR_BODY:%.*]]
+; CHECK: for.body:
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ [[START]], [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]]
+; CHECK-NEXT: [[ADD]] = add nuw i64 [[SUM]], [[UREM]]
+; CHECK-NEXT: [[I]] = shl nuw i64 [[PHI]], 1
+; CHECK-NEXT: [[ICMP:%.*]] = icmp ult i64 [[PHI]], 50000000
+; CHECK-NEXT: br i1 [[ICMP]], label [[FOR_BODY]], label [[FOR_END:%.*]]
+; CHECK: for.end:
+; CHECK-NEXT: ret i64 [[SUM]]
+;
+entry:
+ %start = shl nuw i64 1, %a
+ br label %for.body
+
+for.body:
+ %phi = phi i64 [ %start, %entry ], [ %i, %for.body ]
+ %sum = phi i64 [ 0, %entry ], [ %add, %for.body ]
+ %urem = urem i64 %size, %phi
+ %add = add nuw i64 %sum, %urem
+ %i = shl nuw i64 %phi, 1
+ %icmp = icmp ult i64 %i, 100000000
+ br i1 %icmp, label %for.body, label %for.end
+
+for.end:
+ %r = phi i64 [ %sum, %for.body ]
+ ret i64 %r
+}
+
+define i64 @known_power_of_two_urem_loop_lshr(i64 %size, i64 %a) {
+; CHECK-LABEL: @known_power_of_two_urem_loop_lshr(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[START:%.*]] = shl nuw i64 1, [[A:%.*]]
+; CHECK-NEXT: br label [[FOR_BODY:%.*]]
+; CHECK: for.body:
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ [[START]], [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]]
+; CHECK-NEXT: [[ADD]] = add nuw i64 [[SUM]], [[UREM]]
+; CHECK-NEXT: [[I]] = lshr i64 [[PHI]], 1
+; CHECK-NEXT: [[ICMP_NOT:%.*]] = icmp ult i64 [[PHI]], 2
+; CHECK-NEXT: br i1 [[ICMP_NOT]], label [[FOR_END:%.*]], label [[FOR_BODY]]
+; CHECK: for.end:
+; CHECK-NEXT: ret i64 [[SUM]]
+;
+entry:
+ %start = shl nuw i64 1, %a
+ br label %for.body
+
+for.body:
+ %phi = phi i64 [ %start, %entry ], [ %i, %for.body ]
+ %sum = phi i64 [ 0, %entry ], [ %add, %for.body ]
+ %urem = urem i64 %size, %phi
+ %add = add nuw i64 %sum, %urem
+ %i = lshr i64 %phi, 1
+ %icmp = icmp ugt i64 %i, 0
+ br i1 %icmp, label %for.body, label %for.end
+
+for.end:
+ %r = phi i64 [ %sum, %for.body ]
+ ret i64 %r
+}
+
+
+define i64 @known_power_of_two_urem_loop_ashr(i64 %size, i64 %a) {
+; CHECK-LABEL: @known_power_of_two_urem_loop_ashr(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[FOR_BODY:%.*]]
+; CHECK: for.body:
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ 4096, [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]]
+; CHECK-NEXT: [[ADD]] = add nuw nsw i64 [[SUM]], [[UREM]]
+; CHECK-NEXT: [[I]] = lshr i64 [[PHI]], [[A:%.*]]
+; CHECK-NEXT: [[ICMP_NOT:%.*]] = icmp eq i64 [[I]], 0
+; CHECK-NEXT: br i1 [[ICMP_NOT]], label [[FOR_END:%.*]], label [[FOR_BODY]]
+; CHECK: for.end:
+; CHECK-NEXT: ret i64 [[SUM]]
+;
+entry:
+ br label %for.body
+
+for.body:
+ %phi = phi i64 [ 4096, %entry ], [ %i, %for.body ]
+ %sum = phi i64 [ 0, %entry ], [ %add, %for.body ]
+ %urem = urem i64 %size, %phi
+ %add = add nsw i64 %sum, %urem
+ %i = ashr i64 %phi, %a
+ %icmp = icmp ugt i64 %i, 0
+ br i1 %icmp, label %for.body, label %for.end
+
+for.end:
+ %r = phi i64 [ %sum, %for.body ]
+ ret i64 %r
+}
+
+define i64 @known_power_of_two_urem_loop_ashr_negative(i64 %size, i64 %a) {
+; Cannot deduce induction variable is a power of 2 for ashr if its starting
+; value is equal to sign bit
+;
+; CHECK-LABEL: @known_power_of_two_urem_loop_ashr_negative(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[FOR_BODY:%.*]]
+; CHECK: for.body:
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ -9223372036854775808, [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]]
+; CHECK-NEXT: [[ADD]] = add nsw i64 [[SUM]], [[UREM]]
+; CHECK-NEXT: [[I]] = ashr i64 [[PHI]], [[A:%.*]]
+; CHECK-NEXT: br i1 true, label [[FOR_BODY]], label [[FOR_END:%.*]]
+; CHECK: for.end:
+; CHECK-NEXT: ret i64 [[SUM]]
+;
+entry:
+ br label %for.body
+
+for.body:
+ %phi = phi i64 [ u0x8000000000000000, %entry ], [ %i, %for.body ]
+ %sum = phi i64 [ 0, %entry ], [ %add, %for.body ]
+ %urem = urem i64 %size, %phi
+ %add = add nsw i64 %sum, %urem
+ %i = ashr i64 %phi, %a
+ %icmp = icmp ugt i64 %i, 0
+ br i1 %icmp, label %for.body, label %for.end
+
+for.end:
+ %r = phi i64 [ %sum, %for.body ]
+ ret i64 %r
+}
+
+define i64 @known_power_of_two_urem_loop_ashr_negative_2(i64 %size, i64 %a) {
+; Cannot deduce induction variable is a power of 2 for ashr if its starting
+; value may equal to sign bit.
+;
+; CHECK-LABEL: @known_power_of_two_urem_loop_ashr_negative_2(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[START:%.*]] = shl nuw i64 1, [[A:%.*]]
+; CHECK-NEXT: br label [[FOR_BODY:%.*]]
+; CHECK: for.body:
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ [[START]], [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]]
+; CHECK-NEXT: [[ADD]] = add nsw i64 [[SUM]], [[UREM]]
+; CHECK-NEXT: [[I]] = ashr i64 [[PHI]], 2
+; CHECK-NEXT: [[ICMP_NOT:%.*]] = icmp ult i64 [[PHI]], 4
+; CHECK-NEXT: br i1 [[ICMP_NOT]], label [[FOR_END:%.*]], label [[FOR_BODY]]
+; CHECK: for.end:
+; CHECK-NEXT: ret i64 [[SUM]]
+;
+entry:
+ %start = shl nuw i64 1, %a
+ br label %for.body
+
+for.body:
+ %phi = phi i64 [ %start, %entry ], [ %i, %for.body ]
+ %sum = phi i64 [ 0, %entry ], [ %add, %for.body ]
+ %urem = urem i64 %size, %phi
+ %add = add nsw i64 %sum, %urem
+ %i = ashr i64 %phi, 2
+ %icmp = icmp ugt i64 %i, 0
+ br i1 %icmp, label %for.body, label %for.end
+
+for.end:
+ %r = phi i64 [ %sum, %for.body ]
+ ret i64 %r
+}
+
+define i64 @known_power_of_two_urem_loop_negative(i64 %size, i64 %a) {
+; Cannot deduce induction variable is a power of 2 if the recurrence is not one
+; of the valid arithmetic operations.
+;
+; CHECK-LABEL: @known_power_of_two_urem_loop_negative(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[START:%.*]] = shl nuw i64 1, [[A:%.*]]
+; CHECK-NEXT: br label [[FOR_BODY:%.*]]
+; CHECK: for.body:
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ [[START]], [[ENTRY:%.*]] ], [ [[I:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[SUM:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[ADD:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT: [[UREM:%.*]] = urem i64 [[SIZE:%.*]], [[PHI]]
+; CHECK-NEXT: [[ADD]] = add nuw i64 [[SUM]], [[UREM]]
+; CHECK-NEXT: [[I]] = add nuw i64 [[PHI]], 1
+; CHECK-NEXT: br i1 true, label [[FOR_BODY]], label [[FOR_END:%.*]]
+; CHECK: for.end:
+; CHECK-NEXT: ret i64 [[SUM]]
+;
+entry:
+ %start = shl nuw i64 1, %a
+ br label %for.body
+
+for.body:
+ %phi = phi i64 [ %start, %entry ], [ %i, %for.body ]
+ %sum = phi i64 [ 0, %entry ], [ %add, %for.body ]
+ %urem = urem i64 %size, %phi
+ %add = add nuw i64 %sum, %urem
+ %i = add nuw i64 %phi, 1
+ %icmp = icmp ugt i64 %i, 0
+ br i1 %icmp, label %for.body, label %for.end
+
+for.end:
+ %r = phi i64 [ %sum, %for.body ]
+ ret i64 %r
+}
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