[llvm] [ValueTracking] Support assume in entry block without DT (PR #109264)
Nikita Popov via llvm-commits
llvm-commits at lists.llvm.org
Thu Sep 19 03:22:16 PDT 2024
https://github.com/nikic created https://github.com/llvm/llvm-project/pull/109264
isValidAssumeForContext() handles a couple of trivial cases even if no dominator tree is available. This adds one more for the case where there is an assume in the entry block, and a use in some other block. The entry block always dominates all blocks.
As having context instruction but not having DT is fairly rare, there is not much impact. Only test change is in assume-builder.ll, where less redundant assumes are generated. I've found having this special case is useful for an upcoming change though.
>From f75e3f7e875f3569d54c5e330608a220f7e744a6 Mon Sep 17 00:00:00 2001
From: Nikita Popov <npopov at redhat.com>
Date: Thu, 19 Sep 2024 10:51:11 +0200
Subject: [PATCH] [ValueTracking] Support assume in entry block without DT
isValidAssumeForContext() handles a couple of trivial cases even
if no dominator tree is available. This adds one more for the
case where there is an assume in the entry block, and a use in
some other block. The entry block always dominates all blocks.
As having context instruction but not having DT is pretty rare,
there is not much impact. Only test change is in assume-builder.ll,
where less redundant assumes are generated. Having the special
case is useful for an upcoming change though.
---
llvm/lib/Analysis/ValueTracking.cpp | 3 +-
llvm/test/Transforms/Util/assume-builder.ll | 42 +++++++++------------
2 files changed, 20 insertions(+), 25 deletions(-)
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index ba3ba7cc98136d..56eb3f99b39d2c 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -528,7 +528,8 @@ bool llvm::isValidAssumeForContext(const Instruction *Inv,
if (DT) {
if (DT->dominates(Inv, CxtI))
return true;
- } else if (Inv->getParent() == CxtI->getParent()->getSinglePredecessor()) {
+ } else if (Inv->getParent() == CxtI->getParent()->getSinglePredecessor() ||
+ Inv->getParent()->isEntryBlock()) {
// We don't have a DT, but this trivially dominates.
return true;
}
diff --git a/llvm/test/Transforms/Util/assume-builder.ll b/llvm/test/Transforms/Util/assume-builder.ll
index 47629a22e36965..98ff2a4827d61b 100644
--- a/llvm/test/Transforms/Util/assume-builder.ll
+++ b/llvm/test/Transforms/Util/assume-builder.ll
@@ -567,15 +567,13 @@ define dso_local i32 @_Z6squarePi(ptr %P, ptr %P1, i1 %cond) {
; BASIC-NEXT: store i32 0, ptr [[P1]], align 4
; BASIC-NEXT: br i1 [[COND]], label [[C:%.*]], label [[B]]
; BASIC: B:
-; BASIC-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P]], i64 4), "nonnull"(ptr [[P]]), "align"(ptr [[P]], i64 8) ]
+; BASIC-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[P]], i64 8) ]
; BASIC-NEXT: store i32 0, ptr [[P]], align 8
-; BASIC-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P1]], i64 4), "nonnull"(ptr [[P1]]), "align"(ptr [[P1]], i64 8) ]
; BASIC-NEXT: store i32 0, ptr [[P1]], align 8
; BASIC-NEXT: br label [[C]]
; BASIC: C:
-; BASIC-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P]], i64 4), "nonnull"(ptr [[P]]), "align"(ptr [[P]], i64 32) ]
+; BASIC-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[P]], i64 32) ]
; BASIC-NEXT: store i32 0, ptr [[P]], align 32
-; BASIC-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P1]], i64 4), "nonnull"(ptr [[P1]]), "align"(ptr [[P1]], i64 4) ]
; BASIC-NEXT: store i32 0, ptr [[P1]], align 4
; BASIC-NEXT: ret i32 0
;
@@ -593,15 +591,13 @@ define dso_local i32 @_Z6squarePi(ptr %P, ptr %P1, i1 %cond) {
; ALL-NEXT: store i32 0, ptr [[P1]], align 4
; ALL-NEXT: br i1 [[COND]], label [[C:%.*]], label [[B]]
; ALL: B:
-; ALL-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P]], i64 4), "nonnull"(ptr [[P]]), "align"(ptr [[P]], i64 8) ]
+; ALL-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[P]], i64 8) ]
; ALL-NEXT: store i32 0, ptr [[P]], align 8
-; ALL-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P1]], i64 4), "nonnull"(ptr [[P1]]), "align"(ptr [[P1]], i64 8) ]
; ALL-NEXT: store i32 0, ptr [[P1]], align 8
; ALL-NEXT: br label [[C]]
; ALL: C:
-; ALL-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P]], i64 4), "nonnull"(ptr [[P]]), "align"(ptr [[P]], i64 32) ]
+; ALL-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[P]], i64 32) ]
; ALL-NEXT: store i32 0, ptr [[P]], align 32
-; ALL-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P1]], i64 4), "nonnull"(ptr [[P1]]), "align"(ptr [[P1]], i64 4) ]
; ALL-NEXT: store i32 0, ptr [[P1]], align 4
; ALL-NEXT: ret i32 0
;
@@ -619,15 +615,13 @@ define dso_local i32 @_Z6squarePi(ptr %P, ptr %P1, i1 %cond) {
; WITH-AC-NEXT: store i32 0, ptr [[P1]], align 4
; WITH-AC-NEXT: br i1 [[COND]], label [[C:%.*]], label [[B]]
; WITH-AC: B:
-; WITH-AC-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P]], i64 4), "nonnull"(ptr [[P]]), "align"(ptr [[P]], i64 8) ]
+; WITH-AC-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[P]], i64 8) ]
; WITH-AC-NEXT: store i32 0, ptr [[P]], align 8
-; WITH-AC-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P1]], i64 4), "nonnull"(ptr [[P1]]), "align"(ptr [[P1]], i64 8) ]
; WITH-AC-NEXT: store i32 0, ptr [[P1]], align 8
; WITH-AC-NEXT: br label [[C]]
; WITH-AC: C:
-; WITH-AC-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P]], i64 4), "nonnull"(ptr [[P]]), "align"(ptr [[P]], i64 32) ]
+; WITH-AC-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[P]], i64 32) ]
; WITH-AC-NEXT: store i32 0, ptr [[P]], align 32
-; WITH-AC-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P1]], i64 4), "nonnull"(ptr [[P1]]), "align"(ptr [[P1]], i64 4) ]
; WITH-AC-NEXT: store i32 0, ptr [[P1]], align 4
; WITH-AC-NEXT: ret i32 0
;
@@ -667,12 +661,12 @@ define dso_local i32 @_Z6squarePi(ptr %P, ptr %P1, i1 %cond) {
; FULL-SIMPLIFY-NEXT: store i32 0, ptr [[P1]], align 4
; FULL-SIMPLIFY-NEXT: br i1 [[COND]], label [[C:%.*]], label [[B]]
; FULL-SIMPLIFY: B:
-; FULL-SIMPLIFY-NEXT: call void @llvm.assume(i1 true) [ "ignore"(ptr undef, i64 4), "ignore"(ptr undef), "align"(ptr [[P]], i64 8) ]
+; FULL-SIMPLIFY-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[P]], i64 8) ]
; FULL-SIMPLIFY-NEXT: store i32 0, ptr [[P]], align 8
; FULL-SIMPLIFY-NEXT: store i32 0, ptr [[P1]], align 8
; FULL-SIMPLIFY-NEXT: br label [[C]]
; FULL-SIMPLIFY: C:
-; FULL-SIMPLIFY-NEXT: call void @llvm.assume(i1 true) [ "ignore"(ptr undef, i64 4), "ignore"(ptr undef), "align"(ptr [[P]], i64 32) ]
+; FULL-SIMPLIFY-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[P]], i64 32) ]
; FULL-SIMPLIFY-NEXT: store i32 0, ptr [[P]], align 32
; FULL-SIMPLIFY-NEXT: store i32 0, ptr [[P1]], align 4
; FULL-SIMPLIFY-NEXT: ret i32 0
@@ -830,10 +824,10 @@ define dso_local i32 @terminator(ptr %P) personality ptr @__gxx_personality_v0 {
; BASIC-SAME: (ptr [[P:%.*]]) personality ptr @__gxx_personality_v0 {
; BASIC-NEXT: bb:
; BASIC-NEXT: invoke void @may_throwv2(ptr nonnull [[P]])
-; BASIC-NEXT: to label [[EXIT:%.*]] unwind label [[CATCH:%.*]]
+; BASIC-NEXT: to label [[EXIT:%.*]] unwind label [[CATCH:%.*]]
; BASIC: Catch:
; BASIC-NEXT: [[V:%.*]] = landingpad { ptr, i32 }
-; BASIC-NEXT: catch ptr null
+; BASIC-NEXT: catch ptr null
; BASIC-NEXT: br label [[EXIT]]
; BASIC: Exit:
; BASIC-NEXT: [[DOT0:%.*]] = phi i32 [ 1, [[BB:%.*]] ], [ 0, [[CATCH]] ]
@@ -843,10 +837,10 @@ define dso_local i32 @terminator(ptr %P) personality ptr @__gxx_personality_v0 {
; ALL-SAME: (ptr [[P:%.*]]) personality ptr @__gxx_personality_v0 {
; ALL-NEXT: bb:
; ALL-NEXT: invoke void @may_throwv2(ptr nonnull [[P]])
-; ALL-NEXT: to label [[EXIT:%.*]] unwind label [[CATCH:%.*]]
+; ALL-NEXT: to label [[EXIT:%.*]] unwind label [[CATCH:%.*]]
; ALL: Catch:
; ALL-NEXT: [[V:%.*]] = landingpad { ptr, i32 }
-; ALL-NEXT: catch ptr null
+; ALL-NEXT: catch ptr null
; ALL-NEXT: br label [[EXIT]]
; ALL: Exit:
; ALL-NEXT: [[DOT0:%.*]] = phi i32 [ 1, [[BB:%.*]] ], [ 0, [[CATCH]] ]
@@ -856,10 +850,10 @@ define dso_local i32 @terminator(ptr %P) personality ptr @__gxx_personality_v0 {
; WITH-AC-SAME: (ptr [[P:%.*]]) personality ptr @__gxx_personality_v0 {
; WITH-AC-NEXT: bb:
; WITH-AC-NEXT: invoke void @may_throwv2(ptr nonnull [[P]])
-; WITH-AC-NEXT: to label [[EXIT:%.*]] unwind label [[CATCH:%.*]]
+; WITH-AC-NEXT: to label [[EXIT:%.*]] unwind label [[CATCH:%.*]]
; WITH-AC: Catch:
; WITH-AC-NEXT: [[V:%.*]] = landingpad { ptr, i32 }
-; WITH-AC-NEXT: catch ptr null
+; WITH-AC-NEXT: catch ptr null
; WITH-AC-NEXT: br label [[EXIT]]
; WITH-AC: Exit:
; WITH-AC-NEXT: [[DOT0:%.*]] = phi i32 [ 1, [[BB:%.*]] ], [ 0, [[CATCH]] ]
@@ -869,10 +863,10 @@ define dso_local i32 @terminator(ptr %P) personality ptr @__gxx_personality_v0 {
; CROSS-BLOCK-SAME: (ptr [[P:%.*]]) personality ptr @__gxx_personality_v0 {
; CROSS-BLOCK-NEXT: bb:
; CROSS-BLOCK-NEXT: invoke void @may_throwv2(ptr nonnull [[P]])
-; CROSS-BLOCK-NEXT: to label [[EXIT:%.*]] unwind label [[CATCH:%.*]]
+; CROSS-BLOCK-NEXT: to label [[EXIT:%.*]] unwind label [[CATCH:%.*]]
; CROSS-BLOCK: Catch:
; CROSS-BLOCK-NEXT: [[V:%.*]] = landingpad { ptr, i32 }
-; CROSS-BLOCK-NEXT: catch ptr null
+; CROSS-BLOCK-NEXT: catch ptr null
; CROSS-BLOCK-NEXT: br label [[EXIT]]
; CROSS-BLOCK: Exit:
; CROSS-BLOCK-NEXT: [[DOT0:%.*]] = phi i32 [ 1, [[BB:%.*]] ], [ 0, [[CATCH]] ]
@@ -882,10 +876,10 @@ define dso_local i32 @terminator(ptr %P) personality ptr @__gxx_personality_v0 {
; FULL-SIMPLIFY-SAME: (ptr [[P:%.*]]) personality ptr @__gxx_personality_v0 {
; FULL-SIMPLIFY-NEXT: bb:
; FULL-SIMPLIFY-NEXT: invoke void @may_throwv2(ptr nonnull [[P]])
-; FULL-SIMPLIFY-NEXT: to label [[EXIT:%.*]] unwind label [[CATCH:%.*]]
+; FULL-SIMPLIFY-NEXT: to label [[EXIT:%.*]] unwind label [[CATCH:%.*]]
; FULL-SIMPLIFY: Catch:
; FULL-SIMPLIFY-NEXT: [[V:%.*]] = landingpad { ptr, i32 }
-; FULL-SIMPLIFY-NEXT: catch ptr null
+; FULL-SIMPLIFY-NEXT: catch ptr null
; FULL-SIMPLIFY-NEXT: br label [[EXIT]]
; FULL-SIMPLIFY: Exit:
; FULL-SIMPLIFY-NEXT: [[DOT0:%.*]] = phi i32 [ 1, [[BB:%.*]] ], [ 0, [[CATCH]] ]
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