Use uniforms set to populate VecValuesToIgnore.

For instructions in uniform set, they will not have vector versions so
add them to VecValuesToIgnore.
For induction vars, those only used in uniform instructions or consecutive
ptrs instructions have already been added to VecValuesToIgnore above. For
those induction vars which are only used in uniform instructions or
non-consecutive/non-gather scatter ptr instructions, the related phi and
update will also be added into VecValuesToIgnore set.

The change will make the vector RegUsages estimation less conservative.

Differential Revision: https://reviews.llvm.org/D20474

llvm-svn: 275912

1 files changed, 72 insertions, 4 deletions

diff --git a/llvm/test/Transforms/LoopVectorize/X86/reg-usage.ll b/llvm/test/Transforms/LoopVectorize/X86/reg-usage.ll
index 47a6e1029ed..6133635a8ad 100644
--- a/llvm/test/Transforms/LoopVectorize/X86/reg-usage.ll
+++ b/llvm/test/Transforms/LoopVectorize/X86/reg-usage.ll
@@ -1,9 +1,7 @@
-; RUN: opt < %s -debug-only=loop-vectorize -loop-vectorize -vectorizer-maximize-bandwidth -O2 -S 2>&1 | FileCheck %s
+; RUN: opt < %s -debug-only=loop-vectorize -loop-vectorize -vectorizer-maximize-bandwidth -O2 -mtriple=x86_64-unknown-linux -S 2>&1 | FileCheck %s
+; RUN: opt < %s -debug-only=loop-vectorize -loop-vectorize -vectorizer-maximize-bandwidth -O2 -mtriple=x86_64-unknown-linux -mattr=+avx512f -S 2>&1 | FileCheck %s --check-prefix=AVX512F
 ; REQUIRES: asserts
 
-target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
-target triple = "x86_64-unknown-linux-gnu"
-
 @a = global [1024 x i8] zeroinitializer, align 16
 @b = global [1024 x i8] zeroinitializer, align 16
 
@@ -45,6 +43,45 @@ for.body:
   br i1 %exitcond, label %for.cond.cleanup, label %for.body
 }
 
+define i32 @goo() {
+; For indvars.iv used in a computating chain only feeding into getelementptr or cmp,
+; it will not have vector version and the vector register usage will not exceed the
+; available vector register number.
+; CHECK-LABEL: goo
+; CHECK:      LV(REG): VF = 4
+; CHECK-NEXT: LV(REG): Found max usage: 4
+; CHECK:      LV(REG): VF = 8
+; CHECK-NEXT: LV(REG): Found max usage: 7
+; CHECK:      LV(REG): VF = 16
+; CHECK-NEXT: LV(REG): Found max usage: 13
+entry:
+  br label %for.body
+
+for.cond.cleanup:                                 ; preds = %for.body
+  %add.lcssa = phi i32 [ %add, %for.body ]
+  ret i32 %add.lcssa
+
+for.body:                                         ; preds = %for.body, %entry
+  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+  %s.015 = phi i32 [ 0, %entry ], [ %add, %for.body ]
+  %tmp1 = add nsw i64 %indvars.iv, 3
+  %arrayidx = getelementptr inbounds [1024 x i8], [1024 x i8]* @a, i64 0, i64 %tmp1
+  %tmp = load i8, i8* %arrayidx, align 1
+  %conv = zext i8 %tmp to i32
+  %tmp2 = add nsw i64 %indvars.iv, 2
+  %arrayidx2 = getelementptr inbounds [1024 x i8], [1024 x i8]* @b, i64 0, i64 %tmp2
+  %tmp3 = load i8, i8* %arrayidx2, align 1
+  %conv3 = zext i8 %tmp3 to i32
+  %sub = sub nsw i32 %conv, %conv3
+  %ispos = icmp sgt i32 %sub, -1
+  %neg = sub nsw i32 0, %sub
+  %tmp4 = select i1 %ispos, i32 %sub, i32 %neg
+  %add = add nsw i32 %tmp4, %s.015
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, 1024
+  br i1 %exitcond, label %for.cond.cleanup, label %for.body
+}
+
 define i64 @bar(i64* nocapture %a) {
 ; CHECK-LABEL: bar
 ; CHECK:       LV(REG): VF = 2
@@ -69,3 +106,34 @@ for.body:
   %exitcond = icmp eq i64 %inc, 1024
   br i1 %exitcond, label %for.cond.cleanup, label %for.body
 }
+
+@d = external global [0 x i64], align 8
+@e = external global [0 x i32], align 4
+@c = external global [0 x i32], align 4
+
+define void @hoo(i32 %n) {
+; For c[i] = e[d[i]] in the loop, e[d[i]] is not consecutive but its index %tmp can
+; be gathered into a vector. For VF == 16, the vector version of %tmp will be <16 x i64>
+; so the max usage of AVX512 vector register will be 2.
+; AVX512F-LABEL: bar
+; AVX512F:       LV(REG): VF = 16
+; AVX512F:       LV(REG): Found max usage: 2
+;
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+  %arrayidx = getelementptr inbounds [0 x i64], [0 x i64]* @d, i64 0, i64 %indvars.iv
+  %tmp = load i64, i64* %arrayidx, align 8
+  %arrayidx1 = getelementptr inbounds [0 x i32], [0 x i32]* @e, i64 0, i64 %tmp
+  %tmp1 = load i32, i32* %arrayidx1, align 4
+  %arrayidx3 = getelementptr inbounds [0 x i32], [0 x i32]* @c, i64 0, i64 %indvars.iv
+  store i32 %tmp1, i32* %arrayidx3, align 4
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, 10000
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  ret void
+}