[PATCH] D83035: [InstCombine] Add (vXi1 trunc(lshr(x,c))) -> icmp_eq(and(x,c')) support for non-uniform vectors

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon created this revision.
RKSimon added reviewers: spatel, lebedev.ri.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.

As noted on 46531, we were only performing this transform on uniform vectors as we were using the m_APInt pattern matcher to extract the shift amount.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D83035

Files:
  llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
  llvm/test/Transforms/InstCombine/apint-shift.ll
  llvm/test/Transforms/InstCombine/icmp.ll


Index: llvm/test/Transforms/InstCombine/icmp.ll
===================================================================
--- llvm/test/Transforms/InstCombine/icmp.ll
+++ llvm/test/Transforms/InstCombine/icmp.ll
@@ -2688,9 +2688,8 @@
 
 define <2 x i1> @icmp_and_or_lshr_cst_vec_nonuniform(<2 x i32> %x) {
 ; CHECK-LABEL: @icmp_and_or_lshr_cst_vec_nonuniform(
-; CHECK-NEXT:    [[SHF:%.*]] = lshr <2 x i32> [[X:%.*]], <i32 1, i32 2>
-; CHECK-NEXT:    [[OR:%.*]] = or <2 x i32> [[SHF]], [[X]]
-; CHECK-NEXT:    [[RET:%.*]] = trunc <2 x i32> [[OR]] to <2 x i1>
+; CHECK-NEXT:    [[TMP1:%.*]] = and <2 x i32> [[X:%.*]], <i32 3, i32 5>
+; CHECK-NEXT:    [[RET:%.*]] = icmp ne <2 x i32> [[TMP1]], zeroinitializer
 ; CHECK-NEXT:    ret <2 x i1> [[RET]]
 ;
   %shf = lshr <2 x i32> %x, <i32 1, i32 2>
@@ -2718,9 +2717,8 @@
 define <2 x i1> @icmp_and_or_lshr_cst_vec_nonuniform_commute(<2 x i32> %xp) {
 ; CHECK-LABEL: @icmp_and_or_lshr_cst_vec_nonuniform_commute(
 ; CHECK-NEXT:    [[X:%.*]] = srem <2 x i32> [[XP:%.*]], <i32 42, i32 42>
-; CHECK-NEXT:    [[SHF:%.*]] = lshr <2 x i32> [[X]], <i32 1, i32 2>
-; CHECK-NEXT:    [[OR:%.*]] = or <2 x i32> [[X]], [[SHF]]
-; CHECK-NEXT:    [[RET:%.*]] = trunc <2 x i32> [[OR]] to <2 x i1>
+; CHECK-NEXT:    [[TMP1:%.*]] = and <2 x i32> [[X]], <i32 3, i32 5>
+; CHECK-NEXT:    [[RET:%.*]] = icmp ne <2 x i32> [[TMP1]], zeroinitializer
 ; CHECK-NEXT:    ret <2 x i1> [[RET]]
 ;
   %x = srem <2 x i32> %xp, <i32 42, i32 -42> ; prevent complexity-based canonicalization
Index: llvm/test/Transforms/InstCombine/apint-shift.ll
===================================================================
--- llvm/test/Transforms/InstCombine/apint-shift.ll
+++ llvm/test/Transforms/InstCombine/apint-shift.ll
@@ -331,8 +331,8 @@
 
 define <2 x i1> @test16vec_nonuniform(<2 x i84> %X) {
 ; CHECK-LABEL: @test16vec_nonuniform(
-; CHECK-NEXT:    [[SHR1:%.*]] = lshr <2 x i84> [[X:%.*]], <i84 4, i84 2>
-; CHECK-NEXT:    [[CMP:%.*]] = trunc <2 x i84> [[SHR1]] to <2 x i1>
+; CHECK-NEXT:    [[TMP1:%.*]] = and <2 x i84> [[X:%.*]], <i84 16, i84 4>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne <2 x i84> [[TMP1]], zeroinitializer
 ; CHECK-NEXT:    ret <2 x i1> [[CMP]]
 ;
   %shr = ashr <2 x i84> %X, <i84 4, i84 2>
Index: llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -742,18 +742,21 @@
     // For vectors, we do not canonicalize all truncs to icmp, so optimize
     // patterns that would be covered within visitICmpInst.
     Value *X;
-    const APInt *C;
-    if (match(Src, m_OneUse(m_LShr(m_Value(X), m_APInt(C))))) {
+    Constant *C;
+    if (match(Src, m_OneUse(m_LShr(m_Value(X), m_Constant(C))))) {
       // trunc (lshr X, C) to i1 --> icmp ne (and X, C'), 0
-      APInt MaskC = APInt(SrcWidth, 1).shl(*C);
-      Value *And = Builder.CreateAnd(X, ConstantInt::get(SrcTy, MaskC));
+      Constant *One = ConstantInt::get(SrcTy, APInt(SrcWidth, 1));
+      Constant *MaskC = ConstantExpr::getShl(One, C);
+      Value *And = Builder.CreateAnd(X, MaskC);
       return new ICmpInst(ICmpInst::ICMP_NE, And, Zero);
     }
-    if (match(Src, m_OneUse(m_c_Or(m_LShr(m_Value(X), m_APInt(C)),
+    if (match(Src, m_OneUse(m_c_Or(m_LShr(m_Value(X), m_Constant(C)),
                                    m_Deferred(X))))) {
       // trunc (or (lshr X, C), X) to i1 --> icmp ne (and X, C'), 0
-      APInt MaskC = APInt(SrcWidth, 1).shl(*C) | 1;
-      Value *And = Builder.CreateAnd(X, ConstantInt::get(SrcTy, MaskC));
+      Constant *One = ConstantInt::get(SrcTy, APInt(SrcWidth, 1));
+      Constant *MaskC = ConstantExpr::getShl(One, C);
+      MaskC = ConstantExpr::getOr(MaskC, One);
+      Value *And = Builder.CreateAnd(X, MaskC);
       return new ICmpInst(ICmpInst::ICMP_NE, And, Zero);
     }
   }


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