From 0ce59b8addc59d2b34972ddb581c16fd1e94163b Mon Sep 17 00:00:00 2001
From: bruno <97033386+bruno-at-orange@users.noreply.github.com>
Date: Tue, 16 Apr 2024 10:22:10 +0200
Subject: [PATCH] force gcc optimization to O1 in KWDGPODiscretizer (#239)

With gcc 12.2.0 (on debian 12), gcc seems too agressive. The only way to fix a segmentation fault
is to force the optimization level to O1 instead of O2.

The segmentation fault occured while accessing the variable cell1 which is NULL. By adding the
following (unnecessary) line, the segmentation fault vanishes:
if (cell1==NULL or cell2==NULL) exit(1);

cherry pick from dev commit bfc01f05727fc1b649105edd351a52d70805ba4b PR #163
---
 .github/workflows/pack-debian.yml             |  2 +-
 .../KWDataGridPostOptimizer.cpp               | 34 +++++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/pack-debian.yml b/.github/workflows/pack-debian.yml
index 2a67e38ad..b656a88cd 100644
--- a/.github/workflows/pack-debian.yml
+++ b/.github/workflows/pack-debian.yml
@@ -108,7 +108,7 @@ jobs:
           khiops -v
           khiops_coclustering -v
       - name: Test Khiops installation
-        continue-on-error: ${{ matrix.os == 'debian:11' || matrix.os == 'debian:12' }}
+        continue-on-error: ${{ matrix.os == 'debian:11' }}
         uses: ./.github/actions/test-khiops-install
   test-kni:
     needs: build
diff --git a/src/Learning/KWDataPreparation/KWDataGridPostOptimizer.cpp b/src/Learning/KWDataPreparation/KWDataGridPostOptimizer.cpp
index 1bd9c48cf..5c9a0c6ca 100644
--- a/src/Learning/KWDataPreparation/KWDataGridPostOptimizer.cpp
+++ b/src/Learning/KWDataPreparation/KWDataGridPostOptimizer.cpp
@@ -550,6 +550,19 @@ void KWDGPODiscretizer::InitializeCellFrequencyVector(KWDGPOCellFrequencyVector*
 // Index de l'attribut a post-optimiser (et donc a ignorer pour le calcul de la signature exogene
 static int nKWDGPODiscretizerPostOptimizationAttributeIndex = -1;
 
+// Bug detecte sur debian 12 avec la version 12.2.0 de gcc. Ce bug apparait en release mais pas en debug.
+// On force la compilation en O1 car il doit y avoir une sur-optimisation de gcc en mode 02 :
+// il y a un segmentation fault, gdb indique que cell1 est a NULL.
+// En ajoutant la ligne suivante (inutile) apres les cast, le bug disparait
+// if (cell1==NULL or cell2==NULL) exit(1);
+// Bug similaire dans KWSortableIndex.h, classe KWIntVectorSorter
+#if defined NDEBUG && defined __GNUC__ && !defined __clang__
+#if __GNUC__ >= 12
+#pragma GCC push_options
+#pragma GCC optimize("O1")
+#endif
+#endif
+
 // Fonction de comparaison de deux cellules basee sur leur signature exogene
 int KWDGPODiscretizerCompareCell(const void* elem1, const void* elem2)
 {
@@ -586,6 +599,12 @@ int KWDGPODiscretizerCompareCell(const void* elem1, const void* elem2)
 	return 0;
 }
 
+#if defined NDEBUG && defined __GNUC__ && !defined __clang__
+#if __GNUC__ >= 12
+#pragma GCC pop_options
+#endif
+#endif
+
 void KWDGPODiscretizer::InitializeHashCellDictionary(NumericKeyDictionary* nkdHashCells,
 						     const KWDataGrid* dataGrid) const
 {
@@ -1468,6 +1487,15 @@ void KWDGPOGrouper::InitializeCellFrequencyVector(KWDGPOCellFrequencyVector* cel
 // Index de l'attribut a post-optimiser (et donc a ignorer pour le calcul de la signature exogene
 static int nKWDGPOGrouperPostOptimizationAttributeIndex = -1;
 
+// On force l'optimisation en O1 car il y a un probleme avec gcc v12
+// Cf. pbm similaire pour la methode KWDGPODiscretizerCompareCell
+#if defined NDEBUG && defined __GNUC__ && !defined __clang__
+#if __GNUC__ >= 12
+#pragma GCC push_options
+#pragma GCC optimize("O1")
+#endif
+#endif
+
 // Fonction de comparaison de deux cellules basee sur leur signature exogene
 int KWDGPOGrouperCompareCell(const void* elem1, const void* elem2)
 {
@@ -1504,6 +1532,12 @@ int KWDGPOGrouperCompareCell(const void* elem1, const void* elem2)
 	return 0;
 }
 
+#if defined NDEBUG && defined __GNUC__ && !defined __clang__
+#if __GNUC__ >= 12
+#pragma GCC pop_options
+#endif
+#endif
+
 void KWDGPOGrouper::InitializeHashCellDictionary(NumericKeyDictionary* nkdHashCells, const KWDataGrid* dataGrid) const
 {
 	ObjectArray oaDataGridCells;