From 461ded4631074c7636edd5985ce15b3748f6a9e2 Mon Sep 17 00:00:00 2001 From: Noah Goldstein Date: Sun, 30 Apr 2023 09:33:03 -0500 Subject: [PATCH] [ValueTracking] Add logic for `isKnownNonZero(ssub.sat X, Y)` The logic here is the same for normal `(sub X, Y)`, so just reused `isNonZeroSub`. Alive2 Link: https://alive2.llvm.org/ce/z/9kSkMv Reviewed By: nikic Differential Revision: https://reviews.llvm.org/D149412 --- llvm/lib/Analysis/ValueTracking.cpp | 3 +++ llvm/test/Analysis/ValueTracking/known-non-zero.ll | 7 +------ 2 files changed, 4 insertions(+), 6 deletions(-) diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index 0439f4e..052b1aed 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -2929,6 +2929,9 @@ bool isKnownNonZero(const Value *V, const APInt &DemandedElts, unsigned Depth, if (isKnownNonZero(II->getArgOperand(0), DemandedElts, Depth, Q)) return true; break; + case Intrinsic::ssub_sat: + return isNonZeroSub(DemandedElts, Depth, Q, BitWidth, + II->getArgOperand(0), II->getArgOperand(1)); case Intrinsic::uadd_sat: if (isKnownNonZero(II->getArgOperand(0), DemandedElts, Depth, Q) || isKnownNonZero(II->getArgOperand(1), DemandedElts, Depth, Q)) diff --git a/llvm/test/Analysis/ValueTracking/known-non-zero.ll b/llvm/test/Analysis/ValueTracking/known-non-zero.ll index 61cbe13d..ca158c2 100644 --- a/llvm/test/Analysis/ValueTracking/known-non-zero.ll +++ b/llvm/test/Analysis/ValueTracking/known-non-zero.ll @@ -855,12 +855,7 @@ define i1 @ushl_nonzero_fail_x_maybe_z(i8 %xx, i8 %y, i8 %ind) { define i1 @ssub_sat_nonzero(i8 %xx, i8 %yy, i8 %ind) { ; CHECK-LABEL: @ssub_sat_nonzero( -; CHECK-NEXT: [[XA:%.*]] = and i8 [[XX:%.*]], -65 -; CHECK-NEXT: [[YO:%.*]] = or i8 [[YY:%.*]], 64 -; CHECK-NEXT: [[X:%.*]] = call i8 @llvm.ssub.sat.i8(i8 [[XA]], i8 [[YO]]) -; CHECK-NEXT: [[Z:%.*]] = or i8 [[X]], [[IND:%.*]] -; CHECK-NEXT: [[R:%.*]] = icmp eq i8 [[Z]], 0 -; CHECK-NEXT: ret i1 [[R]] +; CHECK-NEXT: ret i1 false ; %xa = and i8 %xx, 191 %yo = or i8 %yy, 64 -- 2.7.4