[llvm-branch-commits] [llvm] 4ad4190 - [GVN] Correctly set modified status when doing PRE on indices.
Florian Hahn via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Sun Dec 27 14:04:01 PST 2020
Author: Florian Hahn
Date: 2020-12-27T21:58:31Z
New Revision: 4ad41902e8c7481ccf3cdf6e618dfcd1e1fc10fc
URL: https://github.com/llvm/llvm-project/commit/4ad41902e8c7481ccf3cdf6e618dfcd1e1fc10fc
DIFF: https://github.com/llvm/llvm-project/commit/4ad41902e8c7481ccf3cdf6e618dfcd1e1fc10fc.diff
LOG: [GVN] Correctly set modified status when doing PRE on indices.
This patch updates GVN to correctly return the modified status, if PRE
is performed on indices. It fixes a crash when building the test-suite
with EXPENSIVE_CHECKS and LTO.
Added:
llvm/test/Transforms/GVN/PRE/modified-status.ll
Modified:
llvm/lib/Transforms/Scalar/GVN.cpp
llvm/test/Transforms/GVN/PRE/pre-gep-load.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
index 5d37eb73f9b1..30d00758c662 100644
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -1472,13 +1472,14 @@ bool GVN::processNonLocalLoad(LoadInst *LI) {
return false;
}
+ bool Changed = false;
// If this load follows a GEP, see if we can PRE the indices before analyzing.
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(LI->getOperand(0))) {
for (GetElementPtrInst::op_iterator OI = GEP->idx_begin(),
OE = GEP->idx_end();
OI != OE; ++OI)
if (Instruction *I = dyn_cast<Instruction>(OI->get()))
- performScalarPRE(I);
+ Changed |= performScalarPRE(I);
}
// Step 2: Analyze the availability of the load
@@ -1489,7 +1490,7 @@ bool GVN::processNonLocalLoad(LoadInst *LI) {
// If we have no predecessors that produce a known value for this load, exit
// early.
if (ValuesPerBlock.empty())
- return false;
+ return Changed;
// Step 3: Eliminate fully redundancy.
//
@@ -1521,12 +1522,12 @@ bool GVN::processNonLocalLoad(LoadInst *LI) {
// Step 4: Eliminate partial redundancy.
if (!isPREEnabled() || !isLoadPREEnabled())
- return false;
+ return Changed;
if (!isLoadInLoopPREEnabled() && this->LI &&
this->LI->getLoopFor(LI->getParent()))
- return false;
+ return Changed;
- return PerformLoadPRE(LI, ValuesPerBlock, UnavailableBlocks);
+ return Changed || PerformLoadPRE(LI, ValuesPerBlock, UnavailableBlocks);
}
static bool impliesEquivalanceIfTrue(CmpInst* Cmp) {
diff --git a/llvm/test/Transforms/GVN/PRE/modified-status.ll b/llvm/test/Transforms/GVN/PRE/modified-status.ll
new file mode 100644
index 000000000000..6a329db51d7c
--- /dev/null
+++ b/llvm/test/Transforms/GVN/PRE/modified-status.ll
@@ -0,0 +1,60 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -gvn -S %s | FileCheck %s
+
+; Make sure GVN correctly sets the modified status when doing PRE.
+
+define i32 @test(i64 %v, i32* %ptr.1, i32** %ptr.2, i1 %c) {
+; CHECK-LABEL: @test(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[L_0:%.*]] = load i32, i32* [[PTR_1:%.*]], align 4
+; CHECK-NEXT: br i1 [[C:%.*]], label [[IF_THEN:%.*]], label [[IF_END:%.*]]
+; CHECK: if.then:
+; CHECK-NEXT: ret i32 10
+; CHECK: if.end:
+; CHECK-NEXT: [[L_0_EXT:%.*]] = zext i32 [[L_0]] to i64
+; CHECK-NEXT: [[C_2:%.*]] = icmp eq i64 [[L_0_EXT]], 10
+; CHECK-NEXT: br i1 [[C_2]], label [[IF_2_END:%.*]], label [[IF_2_THEN:%.*]]
+; CHECK: if.2.then:
+; CHECK-NEXT: [[GEP_1:%.*]] = getelementptr inbounds i32, i32* [[PTR_1]], i64 [[V:%.*]]
+; CHECK-NEXT: [[L_2:%.*]] = load i32, i32* [[GEP_1]], align 4
+; CHECK-NEXT: [[DOTPRE:%.*]] = zext i32 [[L_2]] to i64
+; CHECK-NEXT: br label [[IF_2_END]]
+; CHECK: if.2.end:
+; CHECK-NEXT: [[REP_0_EXT_PRE_PHI:%.*]] = phi i64 [ [[DOTPRE]], [[IF_2_THEN]] ], [ 10, [[IF_END]] ]
+; CHECK-NEXT: [[REP_0:%.*]] = phi i32 [ [[L_2]], [[IF_2_THEN]] ], [ [[L_0]], [[IF_END]] ]
+; CHECK-NEXT: [[L_3:%.*]] = load i32*, i32** [[PTR_2:%.*]], align 8
+; CHECK-NEXT: [[GEP_2:%.*]] = getelementptr inbounds i32, i32* [[PTR_1]], i64 [[REP_0_EXT_PRE_PHI]]
+; CHECK-NEXT: [[L_4:%.*]] = load i32, i32* [[GEP_2]], align 4
+; CHECK-NEXT: [[GEP_3:%.*]] = getelementptr inbounds i32, i32* [[L_3]], i64 10
+; CHECK-NEXT: [[L_5:%.*]] = load i32, i32* [[GEP_3]], align 4
+; CHECK-NEXT: [[R:%.*]] = add i32 [[L_4]], [[L_5]]
+; CHECK-NEXT: ret i32 [[R]]
+;
+entry:
+ %l.0 = load i32, i32* %ptr.1, align 4
+ br i1 %c, label %if.then, label %if.end
+
+if.then: ; preds = %entry
+ ret i32 10
+
+if.end: ; preds = %entry
+ %l.0.ext = zext i32 %l.0 to i64
+ %c.2 = icmp eq i64 %l.0.ext, 10
+ br i1 %c.2, label %if.2.end, label %if.2.then
+
+if.2.then: ; preds = %if.end
+ %gep.1 = getelementptr inbounds i32, i32* %ptr.1, i64 %v
+ %l.2 = load i32, i32* %gep.1, align 4
+ br label %if.2.end
+
+if.2.end: ; preds = %if.then7, %if.end
+ %rep.0 = phi i32 [ %l.2, %if.2.then ], [ %l.0, %if.end ]
+ %l.3 = load i32*, i32** %ptr.2, align 8
+ %rep.0.ext = zext i32 %rep.0 to i64
+ %gep.2 = getelementptr inbounds i32, i32* %ptr.1, i64 %rep.0.ext
+ %l.4 = load i32, i32* %gep.2, align 4
+ %gep.3 = getelementptr inbounds i32, i32* %l.3, i64 10
+ %l.5 = load i32, i32* %gep.3, align 4
+ %r = add i32 %l.4, %l.5
+ ret i32 %r
+}
diff --git a/llvm/test/Transforms/GVN/PRE/pre-gep-load.ll b/llvm/test/Transforms/GVN/PRE/pre-gep-load.ll
index cfea28eff03c..33f145b70703 100644
--- a/llvm/test/Transforms/GVN/PRE/pre-gep-load.ll
+++ b/llvm/test/Transforms/GVN/PRE/pre-gep-load.ll
@@ -38,7 +38,7 @@ define double @foo(i32 %stat, i32 %i, double** %p) {
; CHECK-NEXT: [[TMP3:%.*]] = phi double* [ [[DOTPRE]], [[ENTRY_SW_BB2_CRIT_EDGE]] ], [ [[TMP0]], [[IF_END]] ]
; CHECK-NEXT: [[ARRAYIDX5:%.*]] = getelementptr inbounds double, double* [[TMP3]], i64 [[IDXPROM3_PRE_PHI]]
; CHECK-NEXT: [[SUB6:%.*]] = fsub double 3.000000e+00, [[TMP2]]
-; CHECK-NEXT: store double [[SUB6]], double* [[ARRAYIDX5]]
+; CHECK-NEXT: store double [[SUB6]], double* [[ARRAYIDX5]], align 8
; CHECK-NEXT: br label [[RETURN]]
; CHECK: sw.default:
; CHECK-NEXT: br label [[RETURN]]
@@ -93,18 +93,15 @@ return: ; preds = %sw.default, %sw.bb2
define void @test_shortcut_safe(i1 %tst, i32 %p1, i32* %a) {
; CHECK-LABEL: @test_shortcut_safe(
-; CHECK-NEXT: br i1 [[TST:%.*]], label [[SEXT1:%.*]], label [[DOTPRE_DEST_CRIT_EDGE:%.*]]
-; CHECK: .pre.dest_crit_edge:
-; CHECK-NEXT: [[DOTPRE1:%.*]] = sext i32 [[P1:%.*]] to i64
-; CHECK-NEXT: br label [[PRE_DEST:%.*]]
+; CHECK-NEXT: br i1 [[TST:%.*]], label [[SEXT1:%.*]], label [[PRE_DEST:%.*]]
; CHECK: pre.dest:
-; CHECK-NEXT: [[DOTPRE_PRE_PHI:%.*]] = phi i64 [ [[DOTPRE1]], [[DOTPRE_DEST_CRIT_EDGE]] ], [ [[IDXPROM2_PRE_PHI:%.*]], [[SEXT_USE:%.*]] ]
-; CHECK-NEXT: br label [[SEXT_USE]]
+; CHECK-NEXT: [[DOTPRE:%.*]] = sext i32 [[P1:%.*]] to i64
+; CHECK-NEXT: br label [[SEXT_USE:%.*]]
; CHECK: sext1:
; CHECK-NEXT: [[IDXPROM:%.*]] = sext i32 [[P1]] to i64
; CHECK-NEXT: br label [[SEXT_USE]]
; CHECK: sext.use:
-; CHECK-NEXT: [[IDXPROM2_PRE_PHI]] = phi i64 [ [[IDXPROM]], [[SEXT1]] ], [ [[DOTPRE_PRE_PHI]], [[PRE_DEST]] ]
+; CHECK-NEXT: [[IDXPROM2_PRE_PHI:%.*]] = phi i64 [ [[IDXPROM]], [[SEXT1]] ], [ [[DOTPRE]], [[PRE_DEST]] ]
; CHECK-NEXT: [[ARRAYIDX3:%.*]] = getelementptr inbounds i32, i32* [[A:%.*]], i64 [[IDXPROM2_PRE_PHI]]
; CHECK-NEXT: [[VAL:%.*]] = load i32, i32* [[ARRAYIDX3]], align 4
; CHECK-NEXT: tail call void @g(i32 [[VAL]])
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